Chapter III: Its Control and Suppression (2)

The roofs of these houses are often made of tiles, but at times the familiar thatched roof is seen. In both cases the supports or rafters are bamboo poles. The principal piece of furniture is the "bale bale," or bedstead, usually made of bamboo, except in the houses of the well-to-do. Small storerooms are often located in the houses, and stables are sometimes built against them. In many cases the family provisions are kept in the house and the cattle are housed here as well.

MANILA LIGHT MATERIAL HOUSES.--If, now, we turn our attention to the average Tondo (Manila) light material house it will be apparent that the description given for the Java village house fairly describes the Tondo house, except that the Philippine house is commonly elevated 2 metres or more above the ground upon bamboo supports (see photographs). The basement is usually enclosed in a manner similar to the principal room of the Java house and the basement room may fairly be compared, structurally and in the matter of its floor, with the one-story Java house. In the Manila house, however, the floor of the upper room takes the place of the roof of the Java house and like it is supported by bamboo timbers.

Here, then, in our enclosed basement story, we have a practical replica of the one-storied Java house.

Here, also, the principal piece of furniture is often a bamboo bed, practically identical with the Java "bale bale," if we may judge from photographs.

In the Java houses the favorite nesting places for rats were found to be the interiors of horizontal bamboo pieces of the roof, house frame and bedstead.

The rat usually gains entrance by gnawing through the natural partitions between the bamboo sections near the outer end of the pole. Our Manila photographs show both the natural open ends of such timbers and the rat-gnawed perforations in the partitions.

In Java, rats also nest in the thatched roofs, as they occasionally do in the Philippines.

NEST MATERIALS.--The materials utilized for nests by rats in Manila and Java seem to be identical also. Straw, dry leaves and pieces of cotton are mentioned in the Java reports. The same materials and additional ones will be found mentioned in our reports upon nests.

The presence of food was also noted in the bamboo nests in Java and we often find articles of food in our Manila nests.

Dr. Korn, P. H. Service, and the writer (T. W. J.) investigated a good many of these bamboo house-timbers and we not only found such evidences of rats as food, rat fæces and nest materials, but in one case a rat was actually driven out of a bamboo nest by introducing a long thin strip of wood. The evidence of similar conditions then is complete.

We also duplicated the experiences of the Java workers in finding dead rats inside of the bamboo house timbers in close proximity to patients sick (or dead) with plague (see memoranda in the case of Esteban Masabik, of 140 Calle Perla, March 22, 1913).

Very extensive rat destruction and cleaning operations, covering a large portion of the city of Manila and including all sections where cases of rat plague or human plague developed, were undertaken and this work was carried on without interruption for about two (2) years. City laborers to the number of 60 to 150 were used and the work was supervised by Sanitary Inspectors Brantigan and Searcy, of the Bureau of Health. During a part of the time a flying column of 50 men, under Sanitary Inspector Hunniecutt, was detached from the main party and employed at placing rat poison.

The total amount of accumulated dirt removed from houses and yards approximated 5250 tons (for 17 months ending November 1, 1913).

Without doubt this general cleaning campaign and the removal of this enormous accumulation of dirt and rubbish was of great value as an antiplague measure.

The rat catch will always be found to depend upon several factors, viz.: the number of persons employed; the number of traps and portions of poison placed; the location of the operations and the length of time a given locality is trapped, poisoned and cleaned. The variety of baits and poisons will also affect the results.

In addition to these factors certain others are found to operate in reducing the rat catch, as, for example, weather conditions and the occurrence of Sundays, holidays and the days just preceding and following holidays.

Upon rainy days and the days just mentioned the rat catch almost invariably falls off.

From statistics collected by me in connection with this work, Dr. V. G. Heiser, then Director of Health for the Philippine Islands, published the following memorandum in 1914. As it is a correct transcript of my records I introduce it here in its entirety.

COMPARATIVE STATISTICS IN RAT-CATCHING METHODS.[3]--With a
view to ascertaining which type of rat trap was most effective
and also the average number of rats that are caught by a given
number of poisoned baits that are set out, statistics were
kept during the antirat campaign in Manila. The ratio
maintained in catching rats with two types of traps is
indicated in the following table, a perusal of which will show
that for the three months ended June 30, 1913, there were
120,565 spring or snap traps set and that for every 100 of
this type of trap set there were caught 6.9 rats. During the
same period there were 47,075 wire cage traps set; the total
number of rats caught was 339; which gives 0.72 rat caught for
each hundred traps set. For the quarter ended September 30,
130,627 spring or snap traps were set and 9,753 rats were
caught, which gives 7.47 for each 100 traps set. During this
period 40,621 wire cage traps were set and 395 rats were
caught, which gives 0.97 rat caught for each 100 wire cage
traps set.

[3] Reprint from the Public Health Reports, Vol. 29, No. 6, February
6, 1914.

===================+==========================+=========================
| Quarter ended June 30 | Quarter ended Sept. 30
+---------+---------+------+---------+---------+-----
Kind of trap | | Number | | | Number |
or poison | Number | of rats | Per | Number | of rats | Per
| set |caught or|cent. | set |caught or|cent.
| |poisoned | | |poisoned |
-------------------+---------+---------+------+---------+---------+-----
Spring or snare | | | | | |
traps | 120,565 | 8,377 | 6.9 | 130,627 | 7,753 | 7.47
Wire cage traps | 47,075 | 339 | .72 | 40,621 | 395 | .97
Poison bacon, rice,| | | | | |
or coconuts | 166,237 | 1,216 | .731| 177,309 | 216 | .12
-------------------+---------+---------+------+-----+---+---------+-----
| Quarter ended--
+---------+---------
| June 30 | Sept. 30
----------------------------------------------------+---------+---------
Number of rats: | |
Caught by dogs | 160 | 5
Killed with clubs and other weapons | 2,889 | 3,818
Found dead from other causes | 316 | 297
----------------------------------------------------+---------+---------

No accurate record was kept of the number of each kind of rat
bait set. Only the total of all was recorded. Bacon or coconut
with strychnine and rice with arsenic were used. For instance,
for the quarter ended June 30, 1913, there were 166,237 poison
baits set in new territory and the rats found poisoned average
for each 100 baits 0.72. During the next quarter there were
177,309 baits set in territory that had been worked over, and
only 216 rats, or 0.12 rat per 100 baits, were killed. From
the foregoing it appears that the rat poison ranks lowest in
efficiency but perhaps highest in economy. In view of the
fact that the original cost of the cage trap is many times
more than that of the spring trap, and the cost of maintenance
is very high, it will be apparent that the spring trap is by
far the more economical as well as more effective of the two.

Generally speaking, however, the number of rat catchers engaged and the location of their operations has the largest influence upon the total catch of rats. For the fiscal year July 1, 1912, to June 30, 1913, inclusive, the total catch was 55,101 rats (Manila only); to December 1, 1913, 79,676.

The most natural explanation of the general correspondence between the highest rat catch and the highest incidence of human plague would be upon grounds of greater activity in rat catching effort at times of greatest plague prevalence, but from the inauguration of general systematic rat catching there was no cessation of effort, even during the abatement of plague, and in consequence this explanation does not apply strictly.

It is true, however, that whenever plague occurred in districts theretofore free from the disease, rat catching was pushed vigorously in the surrounding localities.

Making due allowance for all the factors mentioned I am impressed with the probability, amounting almost to certainty, that the catch of more than 79,676 rats definitely affected and checked the spread of plague in Manila in 1913; and I am of the opinion that systematic and wholesale rat catching, carried out in the most economical manner possible, should be persisted in indefinitely, at least until plague disappears, wherever the disease occurs.

Efforts to prevent the spread of plague to the provinces of Luzon, by way of the railways, were successful and the present measures employed, freight inspection, the fumigation of packages suspected or likely to contain rats, and the similar treatment of freight cars showing signs of rats, should be continued. In a few cases these measures have driven rats out of both packages and cars and the animals have been killed by the sanitarians on duty at the station.

The matter of water transportation was entirely within the control of the authorities in charge of inter-island quarantine affairs.

Rat catching in Manila was systematically performed and all rats captured were turned over to the Bureau of Science for examination for plague.

When plague foci were discovered the localities were trapped and poisoned both circumferentially and centrally, with a view to preventing the diffusion of infected rats throughout the city.

RAT-PROOFING.--The theoretic desirability and superiority of "out building" the rat, over all other methods of rat suppression, is admitted. The apparent impracticability of actually rat-proofing Manila at the present time and our inability to starve the animals out, justify the other and less permanent measure, viz.: rat catching. However, I heartily favor and urge the most complete and thorough-going rat-proofing of buildings actually infected with human or animal plague, in all cases. The building ordinances of Manila already provide for rat-proof construction in all new buildings erected.

With a view to cutting off the food supply of the rat, more than 1100 orders upon householders, to provide covered garbage cans, were served in the district of Tondo alone.

The open ends of bamboo timbers in more than 2300 houses were closed, either by cement or tin cans, during 1913.

THEATRE DISINFECTION.--All the cinematographs and theatres in the city were disinfected upon repeated occasions by spraying with petroleum and cresols, with a view to destroying fleas and preventing plague infection.

Attempts at deception and concealment of plague patients, upon the part of members of their families, were numerous, but with the close scrutiny of death certificates and dead bodies exercised at all health stations it is believed that all cases were recognized.

One case of extremely careless diagnosis occurred. A death certificate was furnished by a local native doctor who certified the cause of death to be "uterine hemorrhage." Suspicion arising, an autopsy was ordered and a pronounced case of bubonic plague was disclosed postmortem. No evidence of uterine hemorrhage, except slight menstrual signs, was found.

The destruction of infected fleas in plague houses is of course the primary object of the disinfection by spraying, which is thoroughly carried out in every house where a case of human plague or rat plague appears. The method is a simple one and consists in spraying a mixture of cresols (2 per cent.) and kerosene (98 per cent.) over all surfaces of the house, floors, walls, underlying ground, furniture and the spaces above ceilings, etc., using the mixture liberally and securing a general surface distribution. There is no doubt of the toxicity of this mixture to all fleas and bed-bugs which it reaches, and it is undoubtedly an effective measure in rendering an infected house safe. All of the instances of multiple house infections, where the cases recurred after disinfection, in Manila, have been in houses where, for one reason or another, the recommended structural rat-proofing has been postponed or where it has not been done. Thus, on Calle San Fernando the sequence of the four cases (their progress by days and in consecutive houses) is explained by the travel of rats through efficient rat runs present in the walls and ceilings, rather than by the passage of fleas through partition walls, from uncommunicating house to house.

So also at Calle Cabildo, where the superstructure of the house was a veritable sieve, there was a series of communicating double walls.

At the house on Calle T. Alonso a similar condition existed, but here the two cases which occurred may have been synchronously infected, or nearly so, previous to disinfection of the premises.

At Calle Comercio, where six days elapsed between two cases, the rooms and building were piled full of merchandise, defeating immediate disinfection, that is, efficient disinfection, until all the merchandise was moved and the rooms were emptied.

At 1364 Calle Sande, Tondo, where 5 cases originated, the infections were undoubtedly almost synchronous and no infection occurred after disinfection of the house, while at 1226 Calle Juan Luna, Tondo, the two cases were plainly infected at about the same time and this previous to disinfecting the premises.

GUINEA-PIGS AS INDICATORS OF INFECTED HOUSES.--The following experiment shows strikingly the necessity for disinfecting houses where human or animal plague cases have occurred.

Upon December 17, 1912, Dr. O. Schöbl, of the Bureau of Science, and myself, placed two healthy guinea-pigs, free from fleas, in a wire trap cage in the house at No. 4 Calle Barraca, a few hours before the house was disinfected, a patient with plague from this house having died within the preceding twelve hours. The cage containing the guinea-pigs was placed exactly where the patient had slept upon the floor, as indicated by the other tenants of the house. Disinfection was delayed for a few hours and the guinea-pigs were left in the house for one day. Upon December 21 one of the guinea-pigs died from typical bubonic plague--anatomically and bacteriologically positive--other inoculated experimental animals also developing the disease.

Other guinea-pigs placed in plague houses on Calle Cabildo and Calle San Fernando, after disinfection of the premises, failed to acquire plague.

NATURAL ENEMIES OF THE FLEA.--It was observed during the studies in Java that certain natural enemies of fleas exist and operate against their laboratory cultivation and their natural reproduction.

Ants of several varieties, large and small red ants and small black ones, were found to be very antagonistic to fleas, both in the larval and adult states, destroying them actively.

Fleas in the laboratory were found to be affected with mites, with a resultant high mortality among the insects. The same parasites were not found upon wild fleas. On account of the prevalence of mites upon the laboratory fleas certain experiments concerning the transmission of plague were vitiated.

The activity of ants in attacking and disposing of rat cadavers found in our antiplague work in Manila was frequently brought to my attention. We invariably included an attack upon ants in treatment of houses known to harbor, or suspected of harboring, plague rats. The combination of kerosene and cresols, elsewhere referred to, was found to be perfectly satisfactory in the destruction of ants; assuming, of course, that the necessary procedure of exposing the ants, by the moving of merchandise, boards or other protecting materials, was performed, so that contact, by spraying the insecticide mixture, was secured.

ACTIVITY OF FLEAS.--It was also observed during the Java studies that the rat flea, while rather lazy, may and does cover distances of five metres and that he sometimes covers eighteen centimetres at a single leap.

In addition to this, of course, there must be considered the possibility of his falling considerable distances.

ZOÖLOGIC CLASSIFICATION OF RATS.--The matter of accurately, systematically and scientifically cataloguing and classifying rats is one of great difficulty and is not to be undertaken by anyone but a trained naturalist. However, some of the notes we have at our disposal, gathered from many sources, may be set before the reader. It is extremely difficult to find exact correspondence of statement in the various classifications offered by writers upon plague and rats.

Dr. Lantz gives the following brief classification in his section of the publication, "The Rat and Its Relation to Public Health."

Order: _Rodentia._

Family: _Muridæ._

Genus: _Mus._

Species are many, but only three or four are cosmopolitan.

Cosmopolitan species: _Mus rattus_--black, brown, and roof
(_Alexandrine_) rat; _Mus decumanus_--gray, barn, wharf,
sewer, and Norway rat.

_Mus rattus_ has many varieties known throughout the world and these are named according to color and habitat.

In addition to the names given in Lantz's classification, we constantly see reference to the black house rat, the brownish-gray rat (_Mus Alexandrinus_), the ordinary ship rat, the field rat, etc.; terms descriptive of habitat and appearance being very loosely applied. Little account is taken, by many, of the well-known variations in the coloration of rats due to climate and season and of the well recognized aptitude of the rat for living in-door or out-door according to circumstances of food supply, weather, etc. The "sawah" rat of Dutch India, implicated in the prevalence of plague there, was formerly considered a variety of _Mus decumanus_, but is now described as a field variety of _Mus rattus_. So too, varieties of _Mus decumanus_ are frequently named according to alleged geographic origin, habitat, color and habits, viz.: sewer rat, brown rat, Norway rat and migratory rat.

The inevitable confusion bound to arise from such loose classification is obvious.

Another genus, _Gunomys_ (_Nesokia_), implicated in plague, is represented in India by two species and by at least one (an undetermined one) in Java, some confusion existing in the matter as yet. Members of this genus are described as large, rough-coated rats which live both as house rats and field rats. In India the Plague Commission reported specimens of this genus as particularly susceptible to plague.

In the Philippine Islands no specimens of _Gunomys_ have been observed, but _M. rattus_ and _M. decumanus_ are both present and numerous and both are subject to plague, as shown by the presence of the disease in specimens examined.

In view of the unreliability of the points of difference in rats usually given as identifying data, such as the number and location of the mammæ, the variations in color and the peculiarities of the footpads, the Javan observers depend upon the conformation of the skulls for the determination of genera, the skull of _M. rattus_ being oval and arched, that of _M. decumanus_ more closely approaching the square and rectangular conformation, and that of _Gunomys_ being broader, higher and longer than either.

In _M. rattus_ the prominent borders which separate the parietal from the frontal surfaces of the skull are oval; in _M. decumanus_ they are parallel or slightly divergent; in _Gunomys_ they are lyre-shaped.

To determine these differences the heads of the rats are cut off, the tissues desiccated by antiformin, or by boiling and stripping.

From experiences in Porto Rico, Creel, of the U. S. Public Health Service, concludes that _M. norvegicus_ (_decumanus_), while essentially a burrowing animal and not addicted to climbing or swimming, is nevertheless quite capable of doing either. He was found to burrow in the hardest earth to a depth of two and one-half feet and to pass through all kinds of wood, soft brick and lime mortar, probably by gnawing.

The black rat and Alexandrine rat (_M. rattus_) in Porto Rico, according to the same observer, do not burrow at all, but can climb and jump in expert manner, and are the species found in the rural districts, remote from houses. He found that all varieties of rats may swim, from ships to the shore, distances of from one-fourth to one-half mile, but that they lack the sense of direction and probably do not land from ships naturally in this manner (_Public Health Reports_, No. 9, February 28, 1913).

The female _decumanus_ is a prolific breeder and brings forth larger litters than the _Mus rattus_ female.

_Mus decumanus_ is generally conceded to be larger and more ferocious than _Mus rattus_. For this reason he drives the smaller rats to the upper floors, the _decumanus_ species generally living near the ground. He is a burrower and is rarely found in the upper stories of buildings. _Decumanus_ is known as a wharf rat, but is rarely trapped on ships on the Pacific Coast, according to the observations of Surgeon Simpson of the U. S. Public Health Service (_Public Health Reports_, April 11, 1913). According to the same observer, _Mus rattus_ is the commonest ship-borne rat. He also states that the black rat and the roof rat (_Alexandrinus_), both varieties of _M. rattus_, differ chiefly in color. They live in upper floors, between ceilings, in walls and roofs and are remarkable climbers as well as being expert rope-walkers and wire-walkers. On account of their natural wariness and caution it is not always easy to induce them to enter or approach traps.

The photographs introduced were taken under my direction in Manila in 1912, 1913 and 1914. Some of them show the character of the house construction in Tondo District, Manila, where plague flourished in 1913. Others illustrate methods of rat-proofing bamboo timbers in houses of light material. These end openings were either closed by introducing cement or by placing tight-fitting tin cans over the ends of the bamboo rafters.

There are many interesting memoranda, gathered and made in connection with our antiplague work in Manila, especially concerning the location and construction of rat nests found by our laborers; the materials used and the fabrication of the nests. Memoranda giving details of rat catching and rat-proofing are also presented and notes showing the location of dead rats found in relation to dead human bodies of plague victims.

Notes concerning cases of multiple house infection are also presented as being of possible interest.

The Javan studies in 1911 and 1912 establish the fact that it is possible to form a fair judgment as to the length of time a rat has been dead, up to ten or twelve days, from the condition and appearance of the rat cadaver, both as to decomposition and drying. A series of 50 rats was studied. It is to be understood that the conditions under which these observations were made were tropical conditions. They would be fairly comparable with summer conditions in America, but should not be followed too closely at other seasons of the year. In my own experience I have observed that ants are likely to attack the cadaver early and to obscure the deductions by their destruction of the body.

Days after death Appearance

First to third day Distention of the abdomen, increasing.

Second to third day Loosening of hair by gentle pulling.

Third to fourth day Loosening of the epidermis by gentle
pulling.

Third to fifth day Perforation of abdominal wall with
collapse and disappearance of distention.
This perforation may result from bursting
of abdominal wall, or through anus, vulva
or thorax.

Fourth to sixth day Moist shrinking of the body. Swarming of
maggots. Spontaneous shedding of tufts of
hair.

Fifth to eighth day Drying of body.

Eighth to twelfth day Complete dryness and rigidity.

Photograph (after _Publications of the Civil Medical Service in Netherlands, India_) shows the progressive postmortem changes in rat cadavers, the numbers indicating the number of days after death.

A COLLECTION OF NOTES CONCERNING RAT RUNS, RAT NESTS, THEIR LOCATION AND OTHER DATA.--Attention is invited to the following collection of notes concerning rat runs, rat nests and their locations and other data collected by the various working parties under the direction of Sanitary Inspectors Brantigan, Renner and Kennard, of Manila.

Special attention has been given to the finding and destroying of rat nests, and in this connection please note that during the month of May, 1913, one party of workmen (20 men) under Inspector Brantigan, killed by hand 511 rats out of a total of 1319. This means that many nests were broken up and that much breeding was interfered with. In June, 1913, two parties (40 men) killed 772 rats by hand out of a total of 3019.

This work occurred in Tondo District in connection with extensive cleaning and moving operations.

At 1279 C. Sandejas[4] 7 rats were found in a nest at the foot of a cluster of bamboo trees, between the trunks. Nest was made of leaves.

[4] C. is abbreviation for Calle, the Spanish term for street.

At 728 C. Velasquez, Tondo, 12 rats were driven from a burrow underneath a thick cement floor by formaldehyde gas delivered in the burrow through a rubber hose. This burrow was in sand and the rats came out about ten minutes after the flow of gas began. All were killed or captured and two or three died from the effects of the gas.

On October 27, 1912, two of the rat terriers belonging to the Bureau of Health caught 192 rats in one storeroom at the Manila Railway Station, in 38 minutes. At various times they have killed from 10 to 25 rats at a single location, in connection with the cleaning and moving work done by the laborers. The dogs caught about 600 rats in all.

On March 11, 1913, 27 rats were caught by laborers at 202 Calle Concha. They were nesting in straw covers which had been removed from bottles.

On March 11, 1913, 13 rats were found beneath a pile of loose tiles at 203 C. Sardinas. The nest was made of fibres from coconut shells and straw.

On March 13, 1913, 12 rats were found among stones scattered in a shallow pile on the ground at C. Conservador (interior). Nest was made of rice chaff and small pieces of cloth.

On March 15, 1913, 9 rats were caught at 1353 C. Anloague on the ground floor beneath a pile of boards. Nest was made of coconut fibre and shavings.

On March 16, 1913, 24 rats were caught at 934 (interior) Velasquez beneath a wood pile. Nest was made of coconut-shell fibre and pieces of cloth.

On March 17, 1913, 14 rats were caught under a pile of hay and straw at 173 Velasquez. Nest was made from straw, chaff and hay.

The following articles of food were found in the above-mentioned nests: chicken bones, rice, coconut, fish and bread.

MEISIC DISTRICT

At 822 Sacristia 6 dead rats found in holes.

At 540 T. Alonso a family of 8 rats was smoked out and all were killed.

At 514 same street 6 rats were smoked out and killed.

At 538, interior, same street, 4 rats were smoked out and killed.

At 546 same street 4 rats were smoked out and killed.

At 715 San Bernardo dead rat found in a hole. Nest made of banana leaves and rags.

At 627, interior, Zacateros, 9 rats were smoked out and killed.

At 669 Benavides 6 rats were smoked out of four runs and were caught.

At 631 Zacateros 2 rats were smoked out and killed.

At 417, interior, Misericordia, 4 rats were secured in two holes under a tile floor. Many rats were caught at this number (interior) in traps.

At 221 Espelita 7 rats were found in a nest made of palm leaves and excelsior; location of run way and nest beneath tile floor.

At 124 Tetuan, in a nest of straw and lint, 5 rats were caught by hand, alive.

At 415 T. Alonso one live rat and 3 dead ones were dug out from beneath a tile floor.

SAMPOLOC DISTRICT

At 1001 Bilibid Viejo there were 5 rat runs, in a Chinese store. Eight rats were secured in a nest under the cement floor. Nest made of straw and paper.

At 928 San Sebastian there were 8 rat runs. In one of them there were caught 8 rats. The nest was made of straw.

At the same address, later, 3 rats were caught in another run and 8 young rats, with eyes still unopened, were found in a nest of straw. A supply of bread was on hand in this nest.

At 629 Tanduay 20 rats and nests of straw and paper were found.

At the same address upon another day another rat run was found and one large rat and 16 small ones were taken from a nest made of rags, straw, and fibres.

PACO DISTRICT

At 1115 San Andres in a Chinese tienda (food store), a long rat run and a nest of rags, straw, and paper, and 30 small rats were found.

One nest in a bamboo tree 30 feet above ground was found. Rats had been observed going up the tree and one was caught at the foot of the tree in a trap.

SAMPOLOC DISTRICT

At 629 Tanduay 14 young rats and a nest of straw, paper and rags were found in a stable.

Same address, later, one rat run and nest of straw and rags with one large rat and 16 small ones were found.

TONDO DISTRICT

March 27, 1913, one rat was caught alive inside of a bamboo timber in house at 51, interior, Pesqueria.

At 631 Azcarraga 4 young rats were found in a nest of paper, leaves, and hay. Chicken bones, crab shells, and rice were present in the nest.

A young python was caught in a lumber yard in the Santa Cruz District in June, 1913. In his stomach was found a half-grown rat. Another snake was caught in a rat trap at the same address about the same time.

PLAN FOR HOUSEHOLD RAT DESTRUCTION.--The following plan for household rat destruction was proposed by me to the Director of Health. It is considered worthy of trial if rat plague appears in new districts.

Proposal for periodic household rat poisoning in Manila.

Proposed that, upon a certain day of each week, rat poison be
issued free to all applicants (householders) in Manila who
agree to place same about their premises, permitting the
poison to remain in place for 48 hours.

Instructions and poison placards to be issued with the
poison. Issues to be made from Station Health Offices and
records of issue to be kept.

Collections of dead rats to be made at the end of 24 hours
and 48 hours by Bureau of Health employees. Poison portions
to be collected and turned in at the Station Health Offices
at the end of 48 hours, that is, at the time of the last rat
collection. Rats to be tagged and examined for plague in the
usual manner.

Due newspaper notice of the plan and of the gratuitous issue
of poison to be given to the people and their coöperation
requested.

Plan to be tested for at least two months.

MULTIPLE HOUSE INFECTION

Memorandum concerning 1364 Calle Sande:

Within 72 hours (April 25-27) five fatal cases of plague, all in Filipinos, occurred in Manila. The five deceased persons lived at 334 C. P. Rada (Meisic), 1419, interior, C. Dagupan, 1364 C. Sande (Tondo), 642 C. Ylala (Meisic), and 1492, interior, C. Dagupan (Tondo).

The following relationships were established by inquiry and investigation and the circumstances point strongly to a common source of infection and to a single geographic focus of plague infection in connection with all of the cases, viz.: at 1364 C. Sande (Tondo).

José Raymundo, boy, aged fifteen, lived at 334 C. P. Rada and
worked daily until taken sick on Tuesday, April 22, at 1364
Sande, in the shop of Simplicio Enriques, a silversmith, who
lived part of the time at the same address.

José Raymundo died of bubonic plague at San Lazaro Hospital
on Friday, April 25, 1913.

Norberta Mendoza, woman, aged fifty-six, lived at 1418,
interior, C. Dagupan. She was the mother-in-law of Simplicio
Enriques, the silversmith at 1364 Sande, and visited her
son-in-law there frequently and within a few days of her last
illness. She was taken sick April 22 and died at 1419,
interior, C. Dagupan, on the morning of April 26. At autopsy
at San Lazaro morgue, the same day, bubonic plague was found
to be present and the cause of her death.

Trinidad Galves, a young woman, aged sixteen, lived at 1364
Sande and was taken sick there on April 25. She was removed
to San Lazaro Hospital and died there April 26, extensive
plague lesions being found at autopsy.

Pablo Banzon, man, aged twenty-six, living at 646 C. Ylaya,
was taken sick on Friday, April 25. He was removed to San
Lazaro Hospital Saturday afternoon and died there Sunday
evening, April 27. He was shown to have plague by
bacteriologic examination made at the Bureau of Science. He
worked at 1364 Sande as a silversmith, with José Raymundo and
was employed by Simplicio Enriques.

Simplicio Enriques, aged twenty-seven, a silversmith,
conducting his business at 1364 C. Sande and employing José
Raymundo and Pablo Banzon, was taken sick about April 23. He
moved to two different houses in the interval between the
onset of his sickness and his transfer to San Lazaro Hospital
on April 27, first to 1419 C. Dagupan, interior, where he
remained until the death of his mother at this house; then to
1492 Dagupan, interior, from which place he was transferred
to San Lazaro Hospital, where he died with bubonic plague a
few days later. Diagnosis was confirmed at autopsy.

The two women were patients of Dr. Hernando of Calle Ylaya. He recognized the case of the elder woman as a probable case of plague, after death, and reported the matter to the Bureau of Health.

The house at 1364 C. Sande is of the type in which cases of rat plague and human plague have recently been found. In our operations to put the house in a safe condition we found one dead rat, mummified, in the basement. Unfortunately, the workmen who swept it out did not note the exact location at which it was found. The house is in the midst of the district where rat plague has raged since early in March, 1913. The basement contained unauthorized and illegal sleeping rooms until a few days before this outbreak when they were removed in the course of our antiplague operations. The building is constructed of bamboo with a nipa thatch roof.

The front part of the basement was paved, but the pavement was undermined and broken. Being convinced that dead plague rats were present in the vicinity of this house and probably within it, I directed that the cement floor under the silversmith shop and the barber shop, located upon the ground floor at this address, be torn up. Accordingly, this was done (April 28) and three dead rats and one live one were found beneath the cement. As the bodies were mummified and unfit for bacteriologic examination they were burned. The living rat was examined at the Bureau of Science but was found to be healthy. The cement floor was broken and permitted fleas from the dead rats to enter the basement room of the house which was occupied by the silversmith shop. The rats doubtless died from plague and the hungry fleas in due time attacked the nearest persons at hand, the unfortunate occupants of the silversmith shop and the two women who frequented the room also.

These facts account for the epidemic at 1364 Sande very completely.

The premises at 1364 Calle Sande were quarantined by the following order:

MANILA, April 27, 1913.

The premises 1364 Sande are hereby declared in Quarantine for
Bubonic Plague by order of the Director of Health.

The inmates will be permitted to leave the building and find
quarters elsewhere, provided they leave their addresses with
the policeman in charge, so that they may be readily found.
They must remain in the District of Tondo. If they remain in
the house they will be obliged to stay in the upper story of
the house and will have to arrange for meals to be sent in.

The barber shop and "platero" shop are hereby ordered closed
until further orders.

By order of the Director of Health.

[Signed] T. W. JACKSON,
_Medical Inspector, in Charge of Plague Suppression_.

Memorandum reporting circumstance surrounding 2 cases of plague at 1226 C. Juan Luna (May 17, 1913):

Valeriano Lausin, aged fourteen, Filipino male, Carmelo maker
by trade but out of work at time he was taken sick, recently
removed to this house from 917 C. Jaboneros where he had been
employed. The patient fixes the date at about a week previous
to his sickness, but the proprietors of 917 Jaboneros are
positive in their statement that he left the place where he
lived and worked, at least two weeks before. This boy
recovered.

The circumstances and especially the occurrence of a second case at 1226 C. Juan Luna, indicate that infection was incurred here.

Moreover, this house is in the midst of a rat-plague infected district.

The house is of bamboo and nipa construction and contained illegal basement rooms until a week ago. About 60 persons lived in this house which was once licensed as a tenement but which is unsanitary in a multitude of ways. Bamboo construction, overcrowding, dirty condition and absence of proper drainage, water-closet, proper kitchens and paved ground floors, together with bad ventilation, made it a dangerous habitation and the added condition of plague infection made it necessary to vacate and quarantine the building.

On May 15, at the daily inspection of contacts in the house 1226 C. Juan Luna, Filomena Suñga, aged nineteen, and a relative of the owner of the building, was found to be sick. Her only symptom was fever, but she was transferred to San Lazaro upon suspicion and promptly developed symptoms of plague. She died in a few days and the diagnosis of plague was verified at autopsy. The following order was issued:

STATION "C," TONDO, BUREAU OF HEALTH,
MANILA, P. I., May 15, 1913.

By order of the Director of Health, the house No. 1226 C.
Juan Luna is declared infected and is quarantined this date,
for Bubonic Plague. The house will be vacated and a policeman
will register the names of all residents and the addresses to
which they remove.

The residents may remove their personal effects but will not
be permitted to return while the quarantine is in effect.

[Signed] T. W. JACKSON,
_Medical Inspector, Station "C," Tondo_.

Memorandum: Human body (dead from plague) and dead rats found in the same basement room. Upon March 21, 1913, a Filipino laborer living at 140 Calle Perla, Tondo, was found dead from bubonic plague.

Upon careful investigation and search of the premises the following findings were disclosed:

One rat, large, mummified and dry and therefore dead for at least one week, was found clinging to a bamboo wall just back of the cot upon which the dead human body was found.

In a section of bamboo, in a timber constituting the ceiling of the basement and also the upper part of the door frame, a rat, dead and dried up, was found. This section was the end section of the timber which was partly covered with nipa thatch, with which the sides of the house were covered. The ends of a number of the outside rafters (bamboo) were found to be gnawed through.

Similar conditions were found in adjoining houses and in one case a live rat was driven out of a nest in the bamboo.

SAMPLE OF DETAILED ORDERS ISSUED.--Sample of detailed orders issued by Medical Inspector in Charge of Plague Suppression. Similar orders were issued whenever new districts were entered or new work undertaken.

Memorandum Order. Effective March 25, 1913:

Beginning to-day, 13 men under Assistant Inspector Parás,
will commence cleaning operations at C. Ostra, extending
from the Bay to C. Sande and will clean towards C. Moriones.
They will be provided with a disinfecting pump and will
disinfect the ground surfaces wherever disturbed, outdoors
and indoors. Cleaning is to be done in the most thorough
manner possible, searching meanwhile for rat nests and rat
harbors; re-piling wood, tiles, stones and merchandise;
moving all movable goods out of doors in their search for
rats and rat-holes or nests. All goods are to be piled above
ground at an elevation of at least one foot. All bamboo beds
and bamboo rafters and parts of the house (in the basements)
made of bamboo or of double walls are to be thoroughly
investigated for rats. All foodstuff attractive for rats is
to be placed in covered boxes or galvanized iron cans, tin
cans or barrels, with tight-fitting covers. Special attention
is to be paid to straw, hay, shavings, grain, rat-holes, and
food.

Two men will be detailed to cement up ends of bamboo and
rat-holes, but will not do general repairing. They will carry
materials for mixing cement as needed and will not be
wasteful of materials.

If this force proves to be insufficient in numbers,
additional men may be detailed from the other working
parties.

[Signed] T. W. JACKSON,
_Medical Inspector in Charge of Plague Suppression_.

Specimen order issued to Sanitary Inspector assisting in Plague Suppression by Medical Inspector in charge.

Sanitary Inspector, Bureau of Health:

Please place the gang of workmen under your charge in the
square bounded by Calles Velasquez, Moriones, Concha and
Manila Bay which is infected with rat plague. Treat the
houses and properties there in the same manner in which other
plague-infected districts have been treated, viz.: by
policing the houses and yards, vacating all basements of
light-material houses in which human habitations are
illegally present; removing (with the consent of the
occupants) all unauthorized basement sleeping places, beds,
platforms, etc., and other illegal structures, closing up the
open ends of bamboo rafters or timbers of the house with tin
or cement.

Where the occupants resist this action sanitary orders should
be issued in the usual manner and interference should be
stopped until the order is served and complied with. There
are a number of most insanitary and unsuitable shelters of
bamboo, tin, etc., used for houses by a number of families in
this square and it is desirable to tear down these huts if
permission can be secured. If permission is refused orders
should be issued on the usual form.

[Signed] T. W. JACKSON,
_In Charge of Plague Suppression_.

Specimen order issued by the Medical Inspector in charge of Plague Suppression.

STATION "C," TONDO, May 21, 1913.

Redistribution of rat catchers and laborers engaged in
antiplague work. Effective May 2, 1913.

Sanitary Inspector Kennard and 20 rat catchers will move into
Tondo District and trap and poison rats in the district
bounded on the west by Manila Bay and on the east by Estero
Reina. The work will be begun at the extreme north water
boundary of this district and will proceed toward the south.

Sanitary Inspector Brantigan with a similar number of rat
catchers (20) will work within the same east and west
boundaries and will begin trapping and poisoning at Calle
Moriones, proceeding north. The poisoning and trapping is to
be done in the most thorough manner possible, as this is a
dangerously infected district and rat-plague must be
controlled and terminated here.

The laborers, 60 men, divided into 4 parties of 15 men each
under Assistant Sanitary Inspectors Jesús, De la Rosa,
Laxamana and Parás, will continue the cleaning operations now
under way on both sides of C. Juan Luna south of C. Moriones
(plague localities in the same neighborhood), and thoroughly
disinfect.

One party of 15 men will work in the vicinity of C. Perla,
vacate basements as habitations, search for dead rats in
yards, houses, bamboos, under broken concrete, etc., and will
close up openings in structural bamboo by means of tin and
cement. Emphasis is placed upon the necessity for permanently
vacating basements and men will be sent back over the ground
daily to see that the persons moved out do not return.
Reports are desired so that prosecutions for violations of
the law may be instituted if necessary.

[Signed] T. W. JACKSON,
_Medical Inspector in Charge of Plague Suppression_.

Specimen order issued to Assistants.

May 4, 1913. STATION "C," BUREAU OF HEALTH:

Please place work parties in (interior) 1627-1629 Sande and
525 C. Azcarraga, to clean, disinfect and thoroughly
investigate these premises and the houses, stables and other
buildings in the vicinity. Search for rats, living and dead,
rat nests and rats in bamboos and wood piles, stone piles,
stables, under planks and elsewhere. Cement the openings in
bamboos in houses or close with tin. Make notes on needed
structural work. Do the work as thoroughly as possible.

[Signed] T. W. JACKSON,
_Medical Inspector in Charge of Plague Suppression_.

METHOD OF PROCEDURE IN COLLECTING AND FORWARDING RATS SUSPECTED OF PLAGUE INFECTION TO THE LABORATORY IN MANILA, P. I.--Rat catching,--trapping and poisoning,--is conducted in accordance with instructions contained in the Sanitary Inspector's Handbook (pp. 36, 37, 38) issued by the Bureau of Health.

Rats are collected in Manila and forwarded to the Bureau of Science for autopsy and for biologic examination for the presence of plague bacilli in the following manner:

The various groups of rat catchers are provided with receptacles (iron pails) and a supply of a mixture of kerosene, cresol and water (kerosene 10 parts, cresol 2 parts; water 88 parts).

In these vessels, filled with the pulicidal mixture, the rats are immersed, with a minimum amount of handling, as soon as they are found (whether in traps or dead from poison).

If captured alive they are killed and then promptly immersed. The mixture must be well shaken or stirred when used, as it separates upon standing. The immersion is, of course, for the purpose of destroying any fleas which may be present upon the captured rat.

A paper tag showing the date and the exact location of the place of capture, with the name or group number of the rat catcher, is next affixed to a foot or to the tail of the rat and firmly tied upon the same, where it remains until the rat cadaver is finally disposed of. This tag is a card of strong Manila paper and the record upon it is made with an ordinary lead-pencil, as both ink and indelible pencil marks are apt to become illegible from wetting, whereas lead-pencil marks are little affected thereby.

If desired, the disinfected tag in any given case of rat plague may be returned to the Bureau of Health, for identification, where an accurate record of every rat captured is kept.

After dipping and tagging, the rats are taken to a central point, again dipped, and placed in large, tightly-covered, galvanized iron cans, in which containers they are delivered to the laboratory by cart, once or twice daily.

THE CASE OF MR. C.--The following are the facts concerning the case of Mr. W. C., a prominent American resident of Manila who suffered and died from plague in 1914.

Mr. C., an editor, was taken ill with plague on the night of September 18, sought medical advice and entered St. Paul's Hospital September 19, and was transferred to San Lazaro Hospital, September 20, with an established clinical and bacteriologic diagnosis of bubonic plague. He survived till September 22.

Upon September 21, in the course of disinfecting the business office of Mr. C., located in a district which had furnished a number of cases of both rat and human plague, a dead rat, mummified, was found in the right hand drawer of his desk and fleas were seen to hop from the drawer upon opening it.

A flea killed by the disinfecting mixture at this desk was identified at the Bureau of Science as a rat flea (_Xenopsylla cheopis_).

The rat cadaver was sent to the Bureau of Science and the following facts were reported from there some days later:

The mummified rat and skeleton were pulverized in a sterile mortar and an emulsion was made and injected into guinea-pigs. The animals died from plague in a few days and plague bacilli were recovered from the tissues, as well as from the rat cadaver, by culture.

A second rat cadaver, found at the same time in the same building, during cleaning operations, was similarly treated with identical results.

There could scarcely be a stronger chain of convincing evidence against the rat and the flea, nor a more complete and convincing explanation of Mr. C.'s death than that afforded by these established facts and official documents. So far as I know there is no more striking case on record in the modern history of plague.

LETTER OF WARNING AND APPEAL.--The following letter of warning and appeal for coöperation was suggested and framed by me February 10, 1914, at the time that extensive rat plague was discovered in the heart of the business district of Manila. I presented it to the Director of Health with a strong recommendation for approval and publication and after consideration he approved and authorized publication upon February 10. No change was made in the wording of the proclamation, but it was issued over the signature of the Director of Health to give added force and authority to the appeal. The results were, as I had hoped they might be, highly beneficial. The taking of the public into the confidence of the health authorities brought about a coöperation, without which our efforts in this difficult situation would have been sadly handicapped. It is my belief that this method should often be used by health authorities, particularly where an intelligent community is threatened.

TO WHOM IT MAY CONCERN:

You are hereby informed that the district bounded by Calles
Rosario, Juan Luna, Dasmariñas and Plaza Calderon (and
possibly the neighborhood bordering upon this congested
district) is a dangerous one for all persons living or
conducting business therein, on account of the presence there
of extensive rat plague. Six human cases (with five deaths)
have recently developed there and many dead rats have been
found. All human cases have been directly traced to rats dead
from plague.

The Bureau of Health is now doing everything within its power
to make this district safe, but the attention of all
citizens, property owners and tenants is called to the fact
that they are required by law to keep their premises free
from rats and to abolish all structural conditions of the
buildings which favor the harboring of rats. This means
rat-proofing, and owners are earnestly urged to perform this
necessary work now, under the direction of the Bureau of
Health.

As a temporary expedient and safeguard all interiors, walls,
floors and ceilings should be sprayed with kerosene daily, or
at intervals of two days, to kill the fleas which carry
plague from rats to human beings. All dark insanitary places
used for living rooms should be vacated at once; all
merchandise should be piled upon trusses at least a foot
above the floor; all straw, shavings and other material
attractive to rats for nesting, should be removed and burned
and all food materials upon which rats may feed and live
should be placed in covered boxes, bins or cans.

All rat-holes should be permanently closed and all broken
cement or masonry should be repaired.

Observance of these instructions may save the lives of
yourselves, your families and your tenants. It is your duty
to do your part in this matter, a part which neither the
Bureau of Health nor the Government can do for you.

Through very great effort the Bureau of Health has controlled
plague in Manila and the Philippine Islands during the last
two years.

Residents must now do their part, and owners of property must
permanently make their buildings safe for tenants, both for
business and residential purposes.

BACTERIOLOGIC OBSERVATIONS MADE BY DR. OTTO SCHÖBL.--The following observations upon the bacteriologic aspect of the Manila epidemic which we are considering were made by Dr. Otto Schöbl of the Biological Laboratory of the Bureau of Science, Manila, and pertain to the cases of the first year of the epidemic. They were printed in the December number of the _Philippine Journal of Science_ in 1913, but as they belong so definitely to the epidemic I am describing and as Dr. Schöbl has expressed his willingness for me to quote them in full, I gladly accept his permission. Dr. Schöbl advanced the possibilities of blood-culture diagnosis to such a point of reliability that it became practically possible for us to expect positive culture in nearly every case of true plague and the whole matter of bacteriologic diagnosis was perfected to a high degree of efficiency under his administration of the laboratory work.

He relates his observations as follows:

During the recent outbreak of plague in Manila, I had the
opportunity to make certain observations which are of
interest. These observations were made in the examination of:
(1) Specimens taken from patients and from dead bodies at
autopsies, (2) samples of blood-sucking insects collected in
houses where plague patients had lived, (3) rodents caught by
trap or poisoned in the parts of the city where plague cases
occurred from time to time, and (4) domestic animals suspected
of plague infection.

I. BACTERIOLOGICAL EXAMINATION OF PLAGUE PATIENTS

In order to secure as early diagnosis as possible, the
following procedure of investigation was adopted: