Chapter II: The Deaf as a Permanent Element of the Population (1)

INCREASE IN THE NUMBER OF THE DEAF IN RELATION TO THE INCREASE IN THE GENERAL POPULATION

Are the deaf to be a permanent element in the constitution of the population? Are they always to be reckoned with in the life of the state and the regard of society? Would it not be well to inquire whether or not deafness may be eliminated, or at least reduced to an appreciable degree? These are questions that present themselves at the outset in a consideration of the relation of the deaf to society, and to them we now devote our attention.

Our first inquiry in the matter is directed to the question whether deafness as a whole is increasing, decreasing or remaining stationary, in relation to the general population. To determine this, we have recourse to the census returns of the deaf in connection with those of the general population. Unfortunately, however, comparisons of the different censuses respecting the deaf are not altogether to be depended upon, for the reason that they have not always been taken on the same basis, and conclusions from them consequently have to be accepted with qualifications. Special census returns of the deaf have been made since 1830; but the censuses of 1830-1870 purport to be of the deaf and dumb; the census of 1880, of the deaf who became deaf under sixteen years of age; that of 1890, of the deaf and dumb; that of 1900, of the totally deaf; and that of 1910, of the deaf and dumb. The results thus obtained are in the main analogous, but there are a certain number of cases included on one basis that would be excluded on another, and _vice versa_.[15]

Taking the statistics as they are, we have the following table,[16] which gives the number of the deaf as found in the several censuses, according to the bases upon which they were made, together with the ratio per million of population.

NUMBER OF THE DEAF ACCORDING TO THE CENSUSES OF 1830-1910

NO. PER
MILLION OF
YEAR NUMBER POPULATION

1830 (the deaf and dumb) 6,106 475 1840 (the deaf and dumb) 7,665 449 1850 (the deaf and dumb) 9,803 423 1860 (the deaf and dumb) 12,821 408 1870 (the deaf and dumb) 16,205 420 1880 (deafness occurring under sixteen) 33,878 675 1890 (the deaf and dumb) 40,592 648 1900 (the totally deaf) 37,426 492 1910 (the deaf and dumb) 43,812 476

From this table there appears to be a steady decrease in the number of the deaf in relation to the general population from 1830 to 1860, this latter year seeming to be the low water mark. From 1860 to 1870 there is a slight increase, and from 1870 to 1880 a very large one, due to some extent to the method of taking the census. From 1880 to 1890 there is a certain decrease, though the proportion is still very high. From 1890 to 1900 there is a very considerable decrease, probably indicating a return to true conditions; and a not negligible decrease from 1900 to 1910.

On the whole, with respect to these statistics, probably the most that we can safely say is that deafness is at least not on the increase relatively among the population, while there is a possibility that at present it is decreasing. For further determinations, we shall have to seek other means of inquiry.

THE ADVENTITIOUSLY DEAF AND THE CONGENITALLY DEAF

We may perhaps best approach the problem of deafness as an increasing or decreasing phenomenon in the population, if we think of the deaf as composed of two great classes: those adventitiously deaf, that is, those who have lost their hearing by some disease or accident occurring after birth, and those congenitally deaf, that is, those who have never had hearing.[17] In regard to the former class, it follows that we are largely interested in the consideration of those diseases, especially those of childhood, which may affect the hearing, and in their prevention or diminution we can endeavor to ascertain how far there are possibilities of reducing the number of the deaf of this class. In the latter case we are called upon to examine some of the great problems involved in the study of heredity, especially in respect to the extent that the offspring is affected by defects or abnormalities of the parent, and to see what, if any, means are at hand to alter conditions that bring about this form of deafness. We shall first discuss the causes of adventitious deafness, together with the possibilities of its prevention and the likelihood of its diminution, and then consider the questions involved in congenital deafness.

ADVENTITIOUS DEAFNESS AND ITS CAUSES

From three-fifths to two-thirds of the cases of deafness are caused adventitiously--by accident or disease. To accidents, however, only a very small part are due, probably less than one-fiftieth of the entire number.[18] Nearly all adventitious deafness results from some disease, either as a primary disease of the auditory organs, or as a sequence or product of some disease of the system, often one of infectious character, the deafness thus constituting a secondary malady or ailment. The larger portion is of the latter type, probably less than a fourth resulting from original ear troubles.[19] In either case deafness occurs usually in infancy or childhood, and does its harm by attacking the middle or internal ear.

From diseases of the middle ear results over one-fourth (27.2 per cent, according to the census) of all deafness, and from diseases of the internal ear, one-fifth (20.7 per cent), very little (0.6 per cent) being caused by disorders of the outer ear. Of the classified cases of deafness, according to the census, 56.3 per cent are due to diseases affecting the middle ear, and 42.7 per cent to diseases affecting the internal. Of diseases of the middle ear, 72 per cent are of suppurative character, often with inflammation or abscess, and 28 per cent non-suppurative, or rather catarrhal in character. Of diseases of the internal ear, 89 per cent are affections of the nerve, and 10 per cent of the labyrinth. It is to be noted that when the affection is of the internal ear, the result is usually total deafness.

By specified diseases, the leading causes of deafness are scarlet fever (11.1 per cent), meningitis (9.6), brain fever (4.7), catarrh (3.6), "disease of middle ear" (3.6), measles (2.5), typhoid fever (2.4), colds (1.6), malarial fever (1.2), influenza (0.7), with smaller proportions from diphtheria, pneumonia, whooping cough, la grippe, and other diseases. A large part of deafness is seen to be due to infectious diseases, the probabilities being that fully one-third is to be so ascribed, with one-fifth from infectious fevers alone.

After birth and under two years of age, the chief causes of deafness are meningitis, scarlet fever, disease of middle ear, brain fever, and measles. From two to five scarlet fever and meningitis are far in the lead, with many cases also from brain fever, disease of middle ear, measles, and typhoid fever. From five to ten scarlet fever alone outdistances all other diseases, followed in order by meningitis, brain fever and typhoid fever. From ten to fifteen the main causes are meningitis, scarlet fever, brain fever, and catarrh; from fifteen to twenty catarrh and meningitis; from twenty to forty catarrh, colds and typhoid fever; and from forty on, catarrh.

The following table[20] will show in detail the several causes of deafness and their respective percentages.

CAUSES OF DEAFNESS

Total classified 48.5
External ear 0.6
Impacted cerumen 0.2
Foreign bodies 0.1
Miscellaneous 0.3
Middle ear 27.2
Suppurative 19.6
Scarlet fever 11.1
Disease of ear 3.6
Measles 2.5
Influenza 0.7
Other causes 1.7
Non-suppurative 7.6
Catarrh 3.6
Colds 1.6
Other causes 2.4
Internal ear 20.7
Labyrinth 1.8
Malarial fever 1.2
Other causes 0.6
Nerves 18.5
Meningitis 9.6
Brain fever 4.7
Typhoid fever 2.4
Other causes 1.8
Brain center 0.3
Miscellaneous 0.1
Unclassified 45.3
Congenital 33.7
Old age 0.3
Military service 1.0
Falls and blows 2.8
Sickness 2.7
Fever 2.0
Hereditary 0.3
Miscellaneous 2.5
Unknown 6.2

In fairly approximate agreement with the returns of the census, are the records of the special schools for the deaf in respect to the causes of deafness in their pupils, with information also as to the amount from the minor diseases. The following table will give the causes by specific diseases, as found in one school, the Pennsylvania Institution, for two years:[21]

CAUSES OF DEAFNESS OF PUPILS IN PENNSYLVANIA INSTITUTION

1906 1907
PER CENT PER CENT

Total number 510 100.0 500 100.0 Born deaf 213 41.8 206 41.2 Scarlet fever 43 8.2 47 9.4 Meningitis 36 7.1 40 8.0 Falls 24 4.7 25 5.0 Diseases of ear and throat 13 2.6 23 4.6 Catarrh and colds 13 2.6 -- -- Measles 18 3.5 18 3.6 Brain fever 17 3.3 16 3.2 Convulsions 14 2.8 13 2.6 Abscesses 10 2.0 12 2.4 La grippe 10 2.0 7 1.4 Accidents (not stated) 9 1.8 7 1.4 Whooping cough 7 1.4 7 1.4 Typhoid fever 7 1.4 6 1.2 Diphtheria 6 1.2 6 1.2 Mumps 5 1.0 5 1.0 Paralysis 5 1.0 4 0.8 Marasmus 2 0.4 4 0.8 Pneumonia 4 0.8 2 0.4 Dentition -- -- 2 0.4 Dropsy of blood 2 0.4 -- -- Chicken pox 1 0.2 1 0.2 Poisoning 1 0.2 1 0.2 Intermittent fever 1 0.2 1 0.2 Blood clotting on brain 1 0.2 -- -- Cholera infantum 1 0.2 -- -- Gastric fever -- -- 1 0.2 Sickness (not stated) 10 2.0 8 1.6 Unknown 37 7.3 38 7.6

POSSIBLE ACTION FOR THE PREVENTION OF ADVENTITIOUS DEAFNESS

In respect to present activities for the prevention of adventitious deafness, we find the situation very much like that of marking time. Deafness, since the beginning of time, has largely been accepted as the portion of a certain fraction of the race, and any serious and determined efforts for its eradication have been considered for the most part as of little hope.[22] With the auditory organs so securely hidden away in the head, entrenched within the protecting temporal bone, and with their structure so delicate and complicated, the problem may well have been regarded a baffling one even for the best labor of medicine and surgery. Hence it is that after deafness has once effected lodgment in the system, a cure has not usually been regarded as within reach, though for certain individual cases there may be medical examination and treatment, with attempts made at relief. For deafness in general, it has been felt that there has been little that could be done in the way of prevention or cure beyond the preservation of the general health and the warding off of diseases that might cause loss of hearing.

As a matter of fact, however, altogether too little attention has been given hitherto to the possibilities of the prevention of deafness. Without question there is much at the outset that can be accomplished towards the prevention of those diseases that cause deafness. A large part, perhaps fully a third, as we have seen, are due to infectious diseases, and it is probably here that measures are likely to be most efficacious. A considerable portion likewise are the result of diseases affecting the passages of the nose and throat, and help should be possible for many of these if taken in hand soon enough. In certain diseases also, as scarlet fever, measles, typhoid fever, diphtheria, and others, there are not a few cases which, so far as deafness as a development is concerned, would prove amenable to skillful and persistent treatment. At the same time due attention to primary ear troubles would in a number of instances keep off permanent deafness. Indeed, it is possible that some thirty or forty per cent of adventitious deafness is preventable by present known means.[23]

Aside from direct medical treatment for those diseases that cause deafness, there are other measures available in a program for the prevention of deafness. One of the foremost essentials is the report to the health authorities of all serious diseases that are liable to result in deafness. In this way proper medical care may be secured, and due precautions may be taken to isolate infectious cases. Even with meningitis, which is so hard usually to deal with and which is so severe in its ravages, there is often some concomitant trouble, and if made notifiable in all cases deafness from it might be checked in no inconsiderable measure. The report of births is also especially needed, and as it becomes obligatory in general, with the consequent detection of physical ailments or disabilities, early cases of deafness may come increasingly to notice, and timely treatment may be availed of. Particular attention is likewise necessary in respect to the medical examination of school children. The proportion of such children with impaired hearing is not slight, even though no great part of them become totally deaf. A committee on defective eyes and ears of school children of the National Educational Association in 1903 found that of 57,072 children examined in seven cities, 2,067, or 3.6 per cent, were extremely defective in hearing.[24] An investigation of the school children in New York City has disclosed the fact that one per cent have seriously defective hearing.[25] Under proper and adequate medical inspection of schools, not only would the need of treatment for adenoids and similar troubles be brought to light, with the result that a number of incipient cases might be stopped in time, but in some instances of deafness already acquired beneficial treatment might be possible.[26]

There is thus a considerable sphere for action towards the prevention of adventitious deafness both by legislation and by education. For the ultimate solution of its problems, however, we have to look mainly to the medical profession. In recent years medical science has won some great triumphs, and in the field of the prevention of deafness no little may be in store to be accomplished in the years to come.[27] Even now, with more particular attention to the diseases of children, and with stronger insistence upon general sanitary measures, the probabilities are that there is less deafness from certain diseases than formerly--a matter which we are soon to consider.

Though as yet there has been little direct action for the prevention of adventitious deafness, there is an increasing concern in the matter, and in this there is promise. By medical bodies in particular is greater attention being given to the subject,[28] and in the widening recognition of their part as guardians of the public health it may be possible for them to do much for the enlightenment of the public. In one state legislative action has been taken expressly for the protection of the hearing of school children. This is Massachusetts, which requires the examination of the eyes and ears of the school children in every town and city, the state board of education furnishing the tests.[29] In some states also general inspection of schools is mandatory by statute, and in others permissive, while in several there are local ordinances with the force of a state law.

In combating adventitious deafness, then, our attack is to be directed in the largest part upon those diseases, especially infantile and infectious diseases, that cause deafness; and it is upon the checking of their spread that our main efforts for the present have to be concentrated. At the same time the better safe-guarding of the general health of the community will insure a proportionate diminution of deafness. Beyond this, we will have to wait upon the developments of medical science, both in the study of the prevention of diseases and of their treatment; and can trust only to what it may offer.[30]

ADVENTITIOUS DEAFNESS AS AN INCREASING OR DECREASING PHENOMENON

Our main interest in the problem of adventitious deafness lies in the possible discovery whether or not it is relatively increasing or decreasing among the population, and in what respects signs appear of a diminution. We have just seen the likelihood of a decrease from certain causes; but we are to find what is indicated by statistical evidence.

To be considered first is adventitious deafness as a whole. Respecting it our only statistics are in the returns of the censuses since 1880, the different forms of deafness not being distinguished before this time. The following table will show the number of the adventitiously deaf as reported by the censuses of 1880, 1890 and 1900, with their respective percentages and ratios per million of population.[31]

NUMBER OF THE ADVENTITIOUSLY DEAF IN 1880, 1890 AND 1900

TOTAL ADVENTITIOUSLY PERCENTAGE RATIO
NUMBER DEAF PER MILLION OF
POPULATION

1880 33,878 10,187 30.1 20.3 1890 40,562 16,767 41.1 26.8 1900 37,426 18,164 48.4 23.9

From this it appears that adventitious deafness is increasing in relation to total deafness, which is most likely the case, as congenital deafness, as we shall see, is evidently decreasing. Whether or not adventitious deafness is increasing in respect to the general population, the table does not disclose definitely. The statistics probably are not full enough to afford any real indication yet.

Our next inquiry is in respect to the increase or decrease of adventitious deafness from the several diseases individually, which is, upon the whole, the more satisfactory test. Here also, unfortunately, our statistics are very limited, and our findings will have to fall much short of what could be desired.

The following table, based on the returns of the censuses of 1880, 1890 and 1900, so far as the approximate identity of the several diseases can be established, will give the respective percentages found.[32]

CAUSES OF ADVENTITIOUS DEAFNESS IN 1880, 1890 AND 1900

1880 1890 1900

Scarlet fever 7.9 11.8 11.1 Meningitis 8.4 7.8 9.6 Catarrh and catarrhal fevers 0.9 3.3 3.6[33] Diphtheria 0.2 0.5 --[34] Abscess and inflammation 1.0 2.5 --[35] Measles 1.3 2.5 2.5 Whooping cough 0.5 0.8 --[34] Malarial and typhoid fevers 1.7 1.8 3.6 Other fevers 1.1 -- 2.0

In this table the most noticeable thing is perhaps the persistency with which we find most of the diseases to recur, with apparently no great change, while in certain ones, as catarrh and malarial and typhoid fevers, there seems to be rather an increase. It would be best, however, not to place very great confidence in these figures, but, so far as the census reports are concerned, to wait for more precise and uniform statistics.

We have, further, the statistics published in the reports of certain schools for the deaf. While these are perhaps not of sufficient extent to warrant full conclusions, they may be regarded as quite representative;[36] and though to be taken with something of the caution as the census figures, they may serve to throw some light upon the situation. Comparison of the proportions of pupils deaf from the several diseases at different times may be made in two ways: by finding the respective proportions over a series of successive years from a certain time back down to the present, and by contrasting the proportions in two widely separated periods, one in the present and one in the past. These will be taken up in order.

The following tables give the percentages of cases of deafness in pupils from the important diseases as found in six schools in successive years: in the New York Institution in the total annual attendance from 1899 to 1912; in the Michigan School in the total biennial attendance from 1883 to 1912; in the Pennsylvania Institution in the number of new pupils admitted quadriennially from 1843 to 1912; in the Western Pennsylvania Institution in the number admitted biennially from 1887 to 1912; in the Maryland School in the number admitted biennially from 1884 to 1911; and in the Wisconsin School in the number admitted biennially from 1880 to 1908.

I. CAUSES OF DEAFNESS IN NEW YORK INSTITUTION FROM 1899 TO 1912

|1899|1900|1901|1902|1903|1904|1905|1906|1907|1908|1909 +----+----+----+----+----+----+----+----+----+----+---- Total Number | 466| 476| 481| 477| 464| 503| 508| 510| 543| 555| 565 +----+----+----+----+----+----+----+----+----+----+---- Congenital |36.0|27.1|26.8|40.9|36.2|41.1|46.2|31.8|33.3|34.4|34.9 Scarlet Fever |11.4|10.1| 8.9| 7.1| 6.5| 6.9| 6.5| 4.9| 5.3| 5.0| 5.7 Meningitis | 9.5| 9.4| 7.7| 7.9| 7.8| 7.9|11.0|12.2|16.8|18.6|17.7 Brain Trouble |10.1| 9.2| 8.3| 8.1| 7.2| 5.9| 5.9| 7.1| 9.0| 8.3| 8.7 Falls | 9.0| 7.2| 5.4| 4.5| 3.9| 4.2| 3.8| 5.2| 5.9| 6.1| 6.0 Measles | 5.1| 3.8| 3.8| 2.1| 3.9| 4.5| 4.1| 4.1| 4.8| 4.7| 4.4 Typhoid Fever | 3.7| 2.3| 1.6| 1.0| 0.9| 1.2| 1.0| 1.0| 1.3| 1.3| 1.2 Convulsions | 3.2| 4.4| 3.2| 2.9| 2.6| 0.2| 1.8| 1.8| 1.9| 1.5| 1.9 Various Fevers | 2.5| 1.5| 1.4| 1.0| 1.7| 1.6| 1.6| 1.6| 1.5| 1.3| 0.7 Catarrh | 2.3| 2.1| 1.9| 1.8| 1.6| 1.2| 1.0| 2.0| 1.9| 1.9| 1.4 Diphtheria | 1.9| 1.7| 1.9| 1.0| 0.9| 0.4| 0.6| 0.8| 0.9| 0.9| 0.7 Pneumonia | 1.5| 0.8| 0.8| 0.6| 1.1| 0.2| 1.0| 1.1| 1.1| 0.9| 1.1 Whooping Cough | 1.7| -- | 1.6| 1.2| 1.1| 1.0| 0.8| 0.6| 0.9| 0.9| 0.5 Miscellaneous | | | | | | | | | | | and Unknown | 2.1|20.4|26.7|19.8|18.6|23.7|14.7|25.9|15.4|14.2|15.1

1910|1911|1912| ----+----+----+ Total Number 570| 546| 518| ----+----+----+ Congenital 32.8|34.6|36.6| Scarlet Fever 6.1| 5.7| 5.0| Meningitis 17.9|19.0|19.7| Brain Trouble 8.3| 8.0| 8.9| Falls 5.1| 5.5| 5.6| Measles 4.6| 0.2| 0.7| Typhoid Fever 1.1| 0.9| 0.5| Convulsions 1.9| 2.0| 2.1| Various Fevers 0.5| 0.5| 0.7| Catarrh 0.8| 1.0| 0.5| Diphtheria 0.7| 0.7| 0.5| Pneumonia 1.1| 0.7| 0.5| Whooping Cough 0.5| 0.5| 0.2| Miscellaneous | | | and Unknown 18.6|20.7|18.5|

II. CAUSES OF DEAFNESS IN MICHIGAN SCHOOL FROM 1883 TO 1912

|1883|1885|1887|1889|1891|1893|1895|1897|1899|1901|1903 |1884|1886|1888|1890|1892|1894|1896|1898|1900|1902|1904 +----+----+----+----+----+----+----+----+----+----+---- Total Number | 302| 336| 342| 350| 343| 365| 428| 412| 441| 447| 451 +----+----+----+----+----+----+----+----+----+----+---- Congenital | 7.0|18.8|23.1|26.3|24.2|26.3|25.2|30.3|28.8|31.5|32.8 Meningitis |28.8|28.1|23.1|23.1|21.3|15.8|15.6|14.5|10.2| 9.2| 4.6 Scarlet Fever |12.2|11.8|12.3|11.2| 9.0| 9.6| 9.5| 9.7| 9.5| 9.3| 7.6 Brain Fever | 6.2| 6.5| 4.8| 3.7| 5.2| 6.9| 6.6| 6.3| 5.4| 3.8| 3.8 Typhoid Fever | 4.6| 3.6| 4.1| 4.3| 4.7| 1.9| 1.8| 1.4| 2.5| 2.2| 1.3 Measles | 3.6| 4.1| 3.9| 2.9| 2.6| 1.4| 0.8| 1.9| 3.2| 3.1| 2.9 Diphtheria | 0.6| -- | -- | 0.3| 0.3| 0.3| 0.2| 0.2| 0.4| 0.2| 0.4 Catarrh | 0.6| 0.6| 0.9| 0.8| 0.9| 1.1| 1.9| -- | 2.9| 3.5| 3.3 Various Fevers | 2.9| 1.5| 2.0| 2.6| 3.0| 4.4| 4.4| 1.7| 2.9| 2.9| 3.3 Whooping Cough | 1.3| 1.2| 1.5| 1.5| 1.5| 3.0| 3.8| 3.6| 2.7| 2.5| 3.1 Pneumonia | -- | -- | -- | -- | -- | -- | -- | -- | 0.2| 0.2| 0.4 La grippe | -- | -- | -- | -- | -- | -- | -- | -- | 0.9| 1.1| 1.6 Miscellaneous | | | | | | | | | | | and Unknown |32.2|23.8|24.3|23.3|27.3|29.3|30.2|30.4|30.4|31.5|34.9

1905|1907|1909|1911| 1906|1908|1910|1912| ----+----+----+----+ Total Number 404| 361| 354| 353| ----+----+----+----+ Congenital 36.6|35.7|35.0|31.2| Meningitis 8.6| 9.5| 8.8| 8.2| Scarlet Fever 6.9| 5.8| 3.6| 4.5| Brain Fever 2.7| 2.5| 2.3| 1.0| Typhoid Fever 1.0| 1.4| 1.5| 1.7| Measles 2.9| 4.1| 3.4| 3.1| Diphtheria 0.5| 0.2| 0.3| 0.3| Catarrh 2.8| 1.9| 2.5| 0.8| Various Fevers 2.5| 0.5| 2.0| 1.4| Whooping Cough 3.4| 4.4| 4.8| 5.1| Pneumonia -- | 0.7| 0.6| 0.8| La grippe 1.5| 3.0| 2.3| -- | Miscellaneous | | | | and Unknown 30.6|30.3|32.9|41.9|

III. CAUSES OF DEAFNESS IN PENNSYLVANIA INSTITUTION FROM 1843 TO 1912

|1843|1847|1851|1855|1859|1863|1867|1871|1875|1879|1883 |1846|1850|1854|1858|1862|1866|1870|1874|1878|1882|1886 +----+----+----+----+----+----+----+----+----+----+---- Total Number | 90| 111| 125| 143| 167| 152| 150| 178| 282| 233| 261 +----+----+----+----+----+----+----+----+----+----+---- Congenital |54.4|58.5|56.0|46.8|53.3|48.4|40.0|42.1|31.2|24.4|34.1 Scarlet Fever |13.3|18.0|12.8|16.8| 9.6|19.7|16.0|18.6|18.1|13.7|14.9 Meningitis | -- | -- | 0.8| -- | -- | 2.0| 1.3| 9.6|18.1|25.7|16.4 Measles | 1.1| 2.7| 1.6| 2.8| 2.4| 3.3| 4.0| 1.1| 1.7| 2.6| 1.9 Whooping Cough | 2.2| 0.9| 0.8| 0.7| 1.2| 0.7| 1.3| 0.6| 0.3| 0.8| -- Catarrh | -- | 0.9| -- | -- | -- | -- | 0.7| 0.6| 2.1| -- | -- Brain Fever | -- | -- | 2.8| 2.1| -- | 6.0| 4.7| -- | -- | -- | 0.8 Typhoid Fever | -- | -- | -- | 1.4| 0.6| 0.7| 2.6| 2.7| 2.1| 2.6| 3.4 Diphtheria | -- | -- | -- | -- | -- | -- | 0.7| -- | -- | -- | -- Pneumonia | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- La grippe | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- Mis. and Unknown |29.0|19.2|25.2|29.4|32.9|19.2|28.7|24.7|26.3|30.2|28.5

1887|1891|1895|1899|1903|1907|1911| 1890|1894|1898|1902|1906|1910|1912| ----+----+----+----+----+----+----+ Total Number 207| 248| 250| 239| 240| 282| 152| ----+----+----+----+----+----+----+ Congenital 47.3|46.8|41.6|32.2|35.8|33.7|34.2| Scarlet Fever 14.0|14.1|11.2| 6.3|10.4| 3.9| 5.2| Meningitis 5.8| 5.6| 7.6| 8.4| 7.1|17.4|15.1| Measles 3.9| 3.2| 4.4| 4.6| 4.5| 3.5| 3.9| Whooping Cough 0.5| 0.4| 0.8| 1.7| 0.7| 2.9| 1.3| Catarrh 3.9| 4.8| 6.8| 4.2| 1.2| 2.5| 1.3| Brain Fever 2.9| 5.2| 4.0| 3.4| 1.7| 2.9| 2.6| Typhoid Fever 2.9| 3.6| -- | 2.5| 0.7| 3.9| 1.3| Diphtheria 0.5| 1.6| 2.0| 0.8| 2.5| 1.2| 2.0| Pneumonia 0.5| -- | -- | 0.8| 0.4| 1.2| 4.8| La grippe -- | 0.4| -- | 2.1| 1.2| 0.3| -- | Mis. and Unknown 17.8|14.3|21.6|33.0|33.8|26.6|28.3|

IV. CAUSES OF DEAFNESS IN WESTERN PENNSYLVANIA INSTITUTION FROM 1887 TO 1912

|1887|1889|1891|1893|1895|1897|1899|1901|1903|1905|1907 |1888|1890|1892|1894|1896|1898|1900|1902|1904|1906|1908 +----+----+----+----+----+----+----+----+----+----+---- Total Number | 61| 56| 58| 58| 49| 40| 50| 41| 110| 59| 73 +----+----+----+----+----+----+----+----+----+----+---- Congenital |24.6|14.3|20.7|32.8|46.9|40.6|40.0|31.9|38.2|25.4|30.1 Scarlet Fever | 9.8|21.4| 8.6|10.4|10.2| 5.0| 6.0|12.2| 8.3|11.8| 8.2 Meningitis |16.5|14.5|13.8|10.4|10.2|20.0|14.0|17.1| 7.2|10.2|13.7 Measles | 4.9| 1.9| 5.2|10.4| 4.0| -- | 2.0| 2.4| 7.2| 1.9| 8.2 Catarrh | 3.2| -- | 7.6| 1.9| 2.0| 5.0| 2.0| 9.6| 2.7| 3.8| 4.1 Brain Fever | 6.5| 5.4| 1.9| 1.9| -- | 2.5| -- | 4.8| 2.7| 5.1| 2.8 Typhoid Fever | -- | 1.9| 5.2| -- | 6.0| 2.5| -- | -- | 1.8| 1.9| 4.1 Whooping Cough | 1.6| -- | 1.9| -- | 2.0| -- | 6.0| 2.4| 1.8| 1.9| 2.8 Diphtheria | 1.6| -- | 1.9| -- | -- | -- | 4.0| 2.4| 1.8| -- | 1.4 La grippe | -- | -- | -- | -- | 2.0| -- | 2.0| -- | -- | 1.9| -- Pneumonia | -- | -- | -- | -- | -- | 2.5| 2.0| -- | -- | 1.9| 1.4 Miscellaneous | | | | | | | | | | | and Unknown |31.3|30.6|33.2|32.2|16.7|22.5|22.0|17.2|28.3|34.2|23.2

1909|1911| 1910|1912| ----+----+ Total Number 71| 73| ----+----+ Congenital 40.9|36.5| Scarlet Fever 11.3|12.7| Meningitis 14.1| 9.6| Measles 2.8| 6.8| Catarrh 2.8| 1.8| Brain Fever 1.4| 4.1| Typhoid Fever 2.8| -- | Whooping Cough -- | 1.8| Diphtheria 1.4| 1.8| La grippe -- | -- | Pneumonia -- | -- | Miscellaneous | | and Unknown 22.5|24.9|

V. CAUSES OF DEAFNESS IN MARYLAND SCHOOL FROM 1884 TO 1911

|1884|1886|1888|1890|1892|1894|1896|1898|1900|1902|1904 |1885|1887|1889|1891|1893|1895|1897|1899|1901|1903|1905 +----+----+----+----+----+----+----+----+----+----+---- Total Number | 28| 27| 25| 25| 29| 30| 30| 39| 29| 30| 28 +----+----+----+----+----+----+----+----+----+----+---- Congenital |46.4|62.9|44.4|36.0|37.9|43.3|43.3|61.5|44.8|43.3|57.1 Meningitis |10.7|11.1| 8.0|12.0|10.3|10.6| 6.7| 2.6|14.0| 3.3| 3.6 Scarlet Fever |10.7| 7.4|12.0|16.0| -- | -- | 6.7| 5.2| 3.5|10.0| 7.2 Measles | 3.6| -- | -- | -- | 3.5| 3.3| 6.7| -- | 3.5| 3.3| -- Diphtheria | -- | -- | -- | -- | 3.5| 3.3| 3.3| 2.6| -- | 3.3| 3.6 Catarrh | -- | -- | -- | -- | 3.5| 3.3| 3.3| 5.2| 3.5| -- | -- Typhoid Fever | -- | -- | 4.0| -- | -- | -- | -- | -- | -- | 6.7| -- Whooping Cough | 3.6| -- | -- | -- | -- | -- | -- | -- | 3.5| -- | -- Pneumonia | 3.6| -- | -- | -- | -- | -- | -- | -- | 7.0| -- | 3.6 Brain Fever | 7.2| -- | 4.0| 8.0| 3.5| 3.3| -- | -- | 7.0| 3.3| -- Various Fevers | -- | -- | 4.0| 8.0| 3.5| -- | -- | 2.6| -- | 3.3| 3.6 Miscellaneous | | | | | | | | | | | and Unknown |14.2|18.6|23.6|20.0|34.3|32.9|28.1|22.0|16.7|23.5|21.3

1906|1908| 1910| 1907|1909| 1911| ----+----+-------+ Total Number 41| 32|135[37]| ----+----+-------+ Congenital 53.7|34.4| 51.8| Meningitis 2.4|12.2| 8.1| Scarlet Fever 9.6| 3.1| 1.4| Measles -- | 3.3| 2.2| Diphtheria -- | -- | 0.7| Catarrh -- | -- | -- | Typhoid Fever 2.4| 3.1| 2.2| Whooping Cough -- | 3.1| 1.4| Pneumonia 2.4| 3.1| 2.2| Brain Fever 4.8| -- | 2.9| Various Fevers 4.8| -- | 2.2| Miscellaneous | | | and Unknown 19.9|37.7| 24.1|

VI. CAUSES OF DEAFNESS IN WISCONSIN SCHOOL FROM 1879 TO 1908

|1879|1881| 1883 |1885|1887|1889|1891|1893|1895|1897 |1880|1882| 1884 |1886|1888|1890|1892|1894|1896|1898 +----+----+-------+----+----+----+----+----+----+---- Total Number | 36| 66|231[37]| 56| 67| 50| 44| 72| 64| 72 +----+----+-------+----+----+----+----+----+----+---- Congenital |14.3|31.8| 35.1|35.7|49.3|38.0|50.0|40.3|53.1|52.7 Meningitis |27.7|33.3| 37.7|33.9|28.3|32.0|15.9|12.5|31.2|19.4 Scarlet Fever |14.3| 6.0| 12.5| -- | 8.9|12.0|20.4|11.1| 4.7| 6.9 Measles |12.8| 3.0| 1.5| -- | 2.9| -- | 2.3| 4.1| 3.1| -- Typhoid Fever | -- | 6.0| 7.4| 1.8| -- | 2.0| 2.3| -- | 1.6| -- Whooping Cough | -- | -- | 1.3| 1.8| 1.5| -- | -- | -- | -- | 1.4 Diphtheria | -- | -- | -- | -- | -- | 2.0| 4.6| -- | -- | 1.4 Catarrh | -- | -- | 1.3| -- | -- | -- | -- | -- | 1.6| 5.5 Brain Fever | -- | -- | -- | -- | 2.9| -- | -- |11.1| -- | -- Miscellaneous | | | | | | | | | | and Unknown |30.9|19.9| 3.2|26.8| 6.2|14.0| 4.5|20.9| 4.7|12.7

1899|1901|1903|1905|1907| 1900|1902|1904|1906|1908| ----+----+----+----+----+ Total Number 62| 33| 33| 63| 70| ----+----+----+----+----+ Congenital 64.3|33.3|48.4|34.9|40.0| Meningitis 16.1| 9.1| 3.0| 6.3| 5.7| Scarlet Fever 4.7| 6.1| -- | 9.5| 8.6| Measles -- | 3.0| 3.6| 1.6| 4.3| Typhoid Fever 3.2| 6.1| -- | 3.2| 1.4| Whooping Cough -- | -- | -- | 1.6| 2.8| Diphtheria 1.6| -- | -- | 3.2| 1.4| Catarrh 1.6| 3.0| 9.1| 3.2| 2.8| Brain Fever -- | 6.1| 3.6| 4.8| 4.3| Miscellaneous | | | | | and Unknown 8.5|33.3|31.3|31.7|28.7|

We may take these tables together to see how the proportions of deafness from the leading diseases have changed in the course of the several periods indicated, proper allowance being made for the shorter length of time covered in some schools than in others. In respect to scarlet fever, one of the two foremost causes, we find in the New York Institution, the Michigan School and the Maryland School, a distinct and steady decline; in the Pennsylvania Institution a decline of late years, which is especially significant in view of the extended period covered by it; and in the Western Pennsylvania and the Wisconsin School little change, though in the latter there is less than at the beginning. In meningitis, on the other hand, the second of the two most important causes, a marked increase is seen in the Pennsylvania Institution for the entire period, while in the New York a sharp increase is found in the time designated, this being all the more noticeable because of the large proportion already attributed here to convulsions, often a trouble of kindred origin. In the Western Pennsylvania Institution and the Maryland School little change is observed, though in the latter some decline is apparent in the later years. In the Wisconsin and Michigan schools a very strong decline is seen. On somewhat the same order as meningitis is brain fever. It, however, shows little change on the whole, though in the Michigan and Maryland schools and the New York Institution some decline is evident. Of the remaining diseases none plays singly a large part in the causation of deafness, and in most of them the results are similar. Measles, typhoid fever, diphtheria, pneumonia, and whooping cough show, with some fluctuations at times, little change on the whole, beyond certain local differences. In the New York Institution a decline is reported in nearly all. In the Pennsylvania Institution a rather larger proportion for measles is seen in later than in earlier years. In the Michigan School an increase seems to be the case with whooping cough, but a decrease with typhoid fever. In catarrh the results are not so uniform. In the New York and Pennsylvania institutions a decline is manifest, though in the latter a larger proportion is reported than at the beginning. In the Michigan and Wisconsin schools rather an increase is noted. La grippe is only reported occasionally of late years, and its real effects cannot yet be ascertained. With respect to general fevers, their classification is found to be so varying that little can be determined.

We now proceed to make comparison of the proportions of deafness from the principal diseases in a series of years some time past with similar proportions in recent years. The following tables give the several proportions in the American School (Connecticut) in the entire attendance from 1817 to 1844 and from 1817 to 1857, and in the new admissions from 1901 to 1913; in the Ohio School in the entire attendance from 1829 to 1872, and in the average annual attendance in 1904, 1905, 1906, and 1911; in the Iowa School in the entire attendance from 1855 to 1870 and from 1855 to 1912; and in the New York Institution in the entire attendance from 1818 to 1853 and in the average annual attendance from 1899 to 1912.[38]

I. CAUSES OF DEAFNESS IN AMERICAN SCHOOL FROM 1817 TO 1844, FROM 1817 TO 1857, AND FROM 1901 TO 1913.

PERIOD |TOTAL NUMBER
| |CONGENITAL
| | |SCARLET FEVER
| | | |MENINGITIS
| | | | |TYPHOID FEVER
| | | | | |MEASLES
| | | | | | |WHOOPING COUGH
| | | | | | | |GENERAL FEVERS
| | | | | | | | |BRAIN FEVER
| | | | | | | | | |PNEUMONIA
| | | | | | | | | | |DIPHTHERIA
| | | | | | | | | | | |CATARRH
| | | | | | | | | | | | |UNKNOWN
| | | | | | | | | | | | |AND MIS.
---------+----+----+----+-----+---+---+---+---+---+---+---+---+--------
1817-1844| 761|44.8| 5.7| 6.1| --|1.6|1.6|6.7| --| --| --| --| 33.5
1817-1857|1081|50.1| 9.2| 4.6| --|1.8|1.3|5.3| --| --| --| --| 27.7
1901-1913| 310|35.2| 7.7| 11.3|3.2|1.3|1.3|1.9|5.8|0.6|1.3|1.0| 29.4

II. CAUSES OF DEAFNESS IN OHIO SCHOOL FROM 1829 TO 1872 AND FROM 1904 TO 1911.

PERIOD |TOTAL NUMBER
| |CONGENITAL
| | |SCARLET FEVER
| | | |MENINGITIS
| | | | |TYPHOID FEVER
| | | | | |MEASLES
| | | | | | |WHOOPING COUGH
| | | | | | | |GENERAL FEVERS
| | | | | | | | |BRAIN FEVER
| | | | | | | | | |PNEUMONIA
| | | | | | | | | | |DIPHTHERIA
| | | | | | | | | | | |CATARRH
| | | | | | | | | | | | |UNKNOWN
| | | | | | | | | | | | |AND MIS.
---------+----+----+----+-----+---+---+---+---+---+---+---+---+--------
1829-1872|1252|33.8|10.3| 3.0|1.8|3.2|1.7|4.6|5.7| --|0.3| --| 35.6
1904-1911| --|38.9| 5.0| 9.2|1.4|2.8|1.7|1.1|5.3|0.5|0.5|3.5| 30.1

III. CAUSES OF DEAFNESS IN IOWA SCHOOL FROM 1855 TO 1870 AND FROM 1855 TO 1912.

PERIOD |TOTAL NUMBER
| |CONGENITAL
| | |SCARLET FEVER
| | | |MENINGITIS
| | | | |TYPHOID FEVER
| | | | | |MEASLES
| | | | | | |WHOOPING COUGH
| | | | | | | |GENERAL FEVERS
| | | | | | | | |BRAIN FEVER
| | | | | | | | | |PNEUMONIA
| | | | | | | | | | |DIPHTHERIA
| | | | | | | | | | | |CATARRH
| | | | | | | | | | | | |UNKNOWN
| | | | | | | | | | | | |AND MIS.
---------+----+----+----+-----+---+---+---+---+---+---+---+---+--------
1855-1870| 245|87.2|13.4| 3.3|1.6|2.0|1.3|6.1|1.3| --| --| --| 33.8
1855-1912|1672|26.9|10.3| 14.9|1.7|2.2|1.7|0.1|7.0|0.3|0.8|1.7| 32.4

IV. CAUSES OF DEAFNESS IN NEW YORK INSTITUTION FROM 1818 TO 1853 AND FROM 1899 TO 1912.

PERIOD |TOTAL NUMBER
| |CONGENITAL
| | |SCARLET FEVER
| | | |MENINGITIS
| | | | |TYPHOID FEVER
| | | | | |MEASLES
| | | | | | |WHOOPING COUGH
| | | | | | | |GENERAL FEVERS
| | | | | | | | |BRAIN FEVER
| | | | | | | | | |PNEUMONIA
| | | | | | | | | | |DIPHTHERIA
| | | | | | | | | | | |CATARRH
| | | | | | | | | | | | |UNKNOWN
| | | | | | | | | | | | |AND MIS.
---------+----+----+----+------+---+---+---+---+---+---+---+---+--------
1818-1853|1148|42.9| 7.2|--[39]| --|1.9|0.7|1.6| --| --| --| --| 45.7
1899-1912| --|38.0| 6.8| 13.1|1.3|3.4|0.8|1.3|8.1|0.9|0.9|1.7| 23.7

Taking these tables also collectively, we find in respect to scarlet fever a decline in all the schools, this being especially pronounced in the case of the Ohio. In meningitis, however, there is an increase so heavy as to call in question the accuracy of the earlier records; and it is possible that it failed to be entirely recognized then. In most of the other diseases, as in the previous case, no very great change is perceptible. In general fevers a decline is apparent in all, in most being considerable; and probably several diseases were formerly included which are now listed separately. In measles rather a decline is found in the American and Ohio schools, but a slight increase in the Iowa, and a somewhat larger one in the New York Institution. In typhoid fever there is a slight increase also in the Iowa School, but a decrease in the Ohio. In brain fever a considerable increase is observed in the Iowa School, but a slight decrease likewise in the Ohio. In whooping cough there is an increase in the New York Institution and the Iowa School, but a decrease in the American. Such diseases as pneumonia, diphtheria and catarrh seem not usually to have been separately classified in the past, though in the Ohio School we find diphtheria noted, and with somewhat smaller proportions than in later years; while in several of the schools we find "colds" given in former times, which may have been in part really catarrh.

Combining now the results of our two groups of tables, we may be able to reach some conclusions with respect to the increase or decrease of deafness from certain diseases, though on the whole far less definite than we could wish. In the first place, it seems safe to affirm that deafness from scarlet fever is becoming relatively less with the years; and it is possible that if it continues its present rate of decline, it will in time cease to be one of the main causes of deafness. On the other hand, meningitis, its great companion in evil, shows a striking increase in comparison with past years, as a cause of adventitious deafness; while its accretion may be traced as well in a series of recent years in certain schools, though not in others. But how far there is an absolute increase in meningitis over the past, and whether it is tending at present actually to increase, may be a matter for question. In view of the possibility that the disease was not sufficiently accounted for in the past, and in the absence of any knowledge to indicate a reason for its less prevalence in earlier years, at least not to the extent indicated by the statistics, it may be that its increase is, after all, more apparent than real. The fact, moreover, that in the series of recent years a marked increase is found in some schools, but a marked decline in others, may perhaps be taken to mean that at present meningitis may be on the increase only in certain sections, depending possibly on local conditions. With the greater medical skill of to-day, and with a larger proportion of children in the schools, it may be open to considerable doubt if the movement of this disease is really one of increase, though it seems that we are on the whole making no great headway against it.

As to the minor diseases causing deafness, our statistics do not indicate just to what extent and in what direction deafness from them is being affected, and no precise conclusions can at present be set down. It is probable, however, that with the increased attention to children's diseases, as we have noted, there is really less deafness from most of them than formerly.[40]

THE CONGENITALLY DEAF

When we come to consider the question of congenital deafness, which comprises a little over a third of the total amount of deafness, we have an even more difficult problem on our hands, for here we are to deal with some of the great questions of heredity--though hereditary deafness and congenital deafness are not altogether one and the same thing.[41] For the purposes of our inquiry, let us think of the congenitally deaf as divided into three great classes in respect to their family relations: 1. the offspring of parents who were cousins; 2. the offspring of parents who were themselves deaf or members of families in which there are other deaf relatives; and 3. the product of families without either consanguinity or antecedent deafness. Of these three classes the first two only will engage our attention. Of the last, comprising, according to the census, nine-twentieths, or 44.4 per cent, of the congenitally deaf, there is not much that we can say. For a great part of it there no doubt exists in the parent, or perhaps in a more remote ancestor, some abnormal strain, physical or mental, in the nature of disease or other defect. But in respect to such deafness we have too little in the way of statistical data to help us arrive at any real determination; and for it as a whole we shall have to wait till we have greater knowledge of eugenics and the laws of heredity.[42]

THE OFFSPRING OF CONSANGUINEOUS MARRIAGES

Not all the deaf born of consanguineous marriages are congenitally deaf, but as the majority are so, and as the fact of the parents being blood relatives is assumed to have at least a contributing influence in the result, we may consider the matter in this place. It is in fact closely connected with the question of deaf relatives in general.

In the census investigations,[43] of the number who answered on this point, 2,525, or 7.4 per cent, have parents who were cousins. Of these cases, deafness occurred in 87 per cent before the fifth year of age, and in 60 per cent at birth. Of all the deaf born without hearing, 13.5 per cent are the offspring of consanguineous marriages. The proportion of those born deaf is thus nearly twice as great when the parents are cousins as it is among the whole class of the congenitally deaf; and the proportion is also nearly twice as great of the offspring of consanguineous marriages among the congenitally deaf as the proportion of the deaf from such marriages among the total number of the deaf. Moreover, 55.0 per cent of the offspring of cousin-marriages have deaf relatives of some kind, and of the congenitally deaf from cousin-marriages, 65.6 per cent have deaf relatives; while the respective proportions when the parents are not cousins are 25.5 per cent and 40.7 per cent--in the one case less than half, and in the other two-thirds, as great.

Further statistics bear out the findings of the census. Dr. E. A. Fay in his "Marriages of the Deaf"[44]--a work we are soon to notice--finds that, though consanguineous marriages form only about one per cent of the total number considered, 30.0 per cent of the children of deaf parents who are cousins are deaf, and that 45.1 per cent of such marriages result in deaf offspring; but that when the parents are not cousins, the respective proportions are 8.3 per cent and 9.3 per cent--only about a fourth and a fifth as great. In the Colorado School, out of 567 pupils in attendance from the beginning to 1912, in 17, or 3 per cent, the parents were related before marriage. In the Kentucky School, out of 83 pupils admitted in 1910 and 1911, 18, or 19.3 per cent, and out of 42 admitted in 1912 and 1913, 8, or 19 per cent, were the offspring of parents who were cousins. In the Iowa School, out of 62 admissions in 1911 and 1912, 4, or 6.5 per cent, and in the Maryland School, out of a total attendance in 1911 of 135, 13, or 9.2 per cent, had parents who were cousins.[45]

Consanguineous marriages, so far as the effect on deafness is concerned, are not of relatively frequent occurrence. But where they do take place, there is found a decided connection between them and deafness, the increased tendency thus to transmit a physical abnormality being plain. How far, however, if at all, such deafness is to be directly ascribed to consanguineous marriages, is a matter for question. The main consideration seems to be that in such marriages the chances are at least doubled of the offspring acquiring the characteristics of the parents; and that in them the liability is thus proportionately enhanced of transmitting deafness.[46]

THE DEAF HAVING DEAF RELATIVES

We are now to examine what traces there may be of deafness in a family by noting what proportion of the deaf have deaf relatives, and are to attempt to see what may be its bearings upon the question of heredity. In the census investigations,[47] we find that out of 34,780 deaf persons who answered, there are 10,033, or 28.8 per cent, who have deaf relatives of some kind, direct or collateral, 8,170, or 23.5 per cent, having deaf brothers, sisters or ancestors. In all of these we can without difficulty discover the influence of heredity. In the congenitally deaf the trace of a physical defect is even more clearly indicated. Of these 40.1 per cent have deaf brothers, sisters or ancestors, and 46.2 per cent have also deaf uncles, cousins, etc.[48]

It is thus evident that there are certain families in society deeply tinged with deafness, that it sometimes passes from parent to child, from generation to generation, and that like a cloud it hangs over a section of the race.

THE OFFSPRING OF DEAF PARENTS

All this argument leads up to one most pertinent question: Are the statistics which we have indicative that this deafness which passes so remorselessly in certain families will be found all the stronger in the children of deaf parents? Have we ground to believe or fear that this deafness will crop out far more surely than in the children of parents not deaf? And can we determine to what extent possibilities are increased of the offspring of deaf parents being likewise deaf?

Let us now consider the statistics which we have in this matter, first examining the results of the census investigation.[49] Of the 8,022 married deaf persons for whom statements are made, we find that there are 190 who have deaf offspring, or 2.4 per cent. Of the 4,116 deaf persons who are married to deaf persons, 137 have deaf children, or 3.3 per cent; and of the 3,906 deaf persons married to hearing persons, 53 have deaf children, or 1.4 per cent. Of the married deaf having deaf children, 52.5 per cent have deaf relatives of some kind, and 54.7 per cent are congenitally deaf, the proportion of those having deaf relatives who are also congenitally deaf being 66.7 per cent. Of the deaf married to hearing partners, who have deaf children, 26.4 per cent are congenitally deaf, while 50.9 per cent of the partners in such marriages have deaf relatives of some kind.

From the census statistics, then, it appears that the married deaf as a class do not have a large proportion of deaf children, and that this proportion is only a little more than twice as great when the deaf are married to the deaf as when they are married to the hearing. It appears also, however, that when there are deaf relatives involved in either kind of marriages, or when there is congenital deafness in the deaf parent, the effect is quite marked in the offspring.

Besides the census returns, we have the statistics presented in the reports of certain schools, which are found to point, as far as they go, to the same conclusions. In the Kentucky School, out of 83 pupils admitted in 1910 and 1911, there were none the children of deaf parents, though 35, or 30.1 per cent, had deaf relatives; and out of 42 admitted in 1912 and 1913, there were 2, or 4.8 per cent, the children of deaf parents, and 12, or 28.8 per cent, with deaf relatives. In the Iowa School, out of 62 admissions in 1911 and 1912, 4, or 6.5 per cent, had deaf parents, and 21, or 33.9 per cent, "defective" relatives. In the Michigan School, with an annual enrollment of some three hundred, there were from 1903 to 1908 but three children of deaf parents.[50] In the Colorado School, out of a total attendance since its founding to 1912 of 567, 3, or 0.57 per cent, were the children of deaf parents, though 83, or 14.6 per cent, had deaf relatives. In the Missouri School, out of a similar attendance to 1912 of 2,174 there were 52, or 2.4 per cent, with deaf parents, though there were 235, or 10.8 per cent, with deaf relatives.[51]

The most exhaustive study of the question of the liability of the deaf to deaf offspring is that of Dr. E. A. Fay in his "Marriages of the Deaf"--covering the majority of the marriages of the deaf in America at the time it was made (1898).[52] Statistical information is presented for 7,227 deaf persons and for 3,078 marriages with either deaf or hearing partners.[53] In the following table are summarized the results of this investigation.[54]

MARRIAGES OF DEAF PERSONS

NUMBER OF NUMBER OF MARRIAGES CHILDREN ---------------------------------+------+---------+-----+------+----+----- Partners in Marriage |Total |Resulting|Per |Total |Deaf|Per | |in deaf |cent | | |cent | |children | | | | ---------------------------------+------+---------+-----+------+----+----- One or both deaf | 3,078| 300| 9.7| 6,782| 588| 8.6 | | | | | | Both deaf | 2,377| 220| 9.2| 5,072| 429| 8.4 One deaf, other hearing | 599| 75| 12.5| 1,532| 151| 9.8 | | | | | | One or both congenitally deaf | 1,477| 194| 13.1| 3,401| 413| 12.1 One or both adventitiously deaf | 2,212| 124| 5.6| 4,701| 199| 4.2 | | | | | | Both congenitally deaf | 335| 83| 24.7| 779| 202| 25.9 One congenitally, other | | | | | | adventitiously deaf | 814| 66| 8.1| 1,820| 119| 6.5 Both adventitiously deaf | 845| 30| 3.5| 1,720| 40| 2.3 | | | | | | One congenitally deaf, other | | | | | | hearing | 191| 28| 14.6| 528| 63| 11.9 One adventitiously deaf, other | | | | | | hearing | 310| 10| 3.2| 713| 16| 2.2 | | | | | | Both had deaf relatives | 437| 103 | 23.5| 1,060| 222| 20.9 One had deaf relatives, other not| 541| 36 | 6.6| 1,210| 78| 6.4 Neither had deaf relatives | 471| 11 | 2.3| 1,044| 13| 1.2 | | | | | | _Both congenitally deaf_ | | | | | | Both had deaf relatives | 172| 49 | 28.4| 429| 130| 30.3 One had deaf relatives, other not| 49| 8 | 16.3| 105| 21| 20.0 Neither had deaf relatives | 14| 1 | 7.1| 24| 1| 4.1 | | | | | | _Both adventitiously deaf_ | | | | | | Both had deaf relatives | 57| 10 | 17.5| 114| 11| 9.6 One had deaf relatives, other not| 167| 7 | 4.1| 357| 10| 2.8 Neither had deaf relatives | 284| 2 | 0.7| 550| 2| 0.3 | | | | | | Partners consanguineous | 31| 14 | 45.1| 100| 30| 30.0

It is thus seen that 9.7 per cent of the marriages of the deaf result in deaf offspring, and that 8.6 per cent of the children born of them are deaf--proportions far greater than for the the population generally.[55] A striking fact to be noted, however, is that these proportions are greater when one parent is deaf and the other hearing than when both are deaf. The percentage of marriages resulting in deaf offspring when only one parent is deaf is 12.5, and when both are deaf, 9.2; while the percentage of deaf children born of them when only one parent is deaf is 9.8, and when both are deaf, 8.4. This is apparently a very strange result, though it probably may be accounted for in some part on the theory that it is not so much deafness itself that is inherited, but rather an abnormality of the auditory organs, or a tendency to disease, of which deafness is a result or symptom, and that with different pathological conditions in the parent there is less likelihood of deafness resulting.

The most significant part of the results seems to be found, as before, in respect to whether or not deaf parents are themselves congenitally deaf or have deaf relatives. On the one hand, when one or both of the parents are adventitiously deaf, the percentage of marriages resulting in deaf children is 5.6, and the percentage of deaf children is 4.2; when both parents are so, the percentages are lower: 3.5 and 2.3. The percentages rise when one parent is adventitiously deaf, and the other congenitally: 8.1 and 6.5. In respect to deaf relatives of parents, the percentages are very low when neither has such relatives: 2.3 and 1.2. The lowest percentages of all are in the case where both parents are adventitiously deaf and neither has deaf relatives: 0.7 and 0.3.