Chapter XIX: Lead and Its Compounds (1)

Of all the metals employed in the arts and industries, none lends itself to such general applicability as lead. In its metallic state it is so plastic that it can be readily moulded. It forms compounds which for colour and persistence have enduring properties superior to most of the metals. There are few articles of manufacture that have not been directly or indirectly brought into contact with lead, and in many of the newer industries the association is extremely close. The census for 1891 showed that there were 132,010 persons employed in lead processes. Of these, 123,829 were painters, 2431 workers in leaden goods, and 5750 were lead-miners. If we add to these the numbers employed in the potteries, electric accumulator works, etc., it will be at once seen that a very large proportion of the artisan class is brought into contact with lead. It is this wide use of the metal, the extremely poisonous character of its compounds, and the peculiarly subtle manner in which they act upon the human organism, that make lead a dangerous substance. Besides, it is frequently present in the water, the aërated beverages, and the wine we drink; the food we eat may be contaminated by having been cooked in common earthenware or in cheap enamelled pots, or by tinning as in canned goods. The acid juices of fruits or foods may dissolve out the lead in the solder. The clothing we wear may have been dyed by lead compounds, and thus not only industrially but in our domestic and personal lives we are daily running the risk of plumbism.

_Lead-mining and the Health and Surroundings of the Miner._

Professor Louis, in his article on Mining, p. 538, has briefly alluded to lead-mining. As in the following pages the subject of lead generally is dealt with, I feel that the reader will have a fuller grasp of all the points relating to lead and its history, if I slightly amplify what he has said by throwing a little side-light upon the medical and social aspects of the lead-miner’s life. Lead-mining in this country is an extremely old industry. Bars of pig-lead have been found in Derbyshire stamped with the imperial arms of Rome, indicating that the Romans worked our mines and smelted the ore. Since 1401 lead-mining has been carried on in the North of England, and has given employment to many families in the remote dales of Cumberland and Durham. It was formerly a source of very great wealth, but the mines have been gradually closing, owing to the importation of cheaper lead and of ores richer in silver than those that exist in this country. To-day it is rather a decaying than a prosperous industry. At present only 15,000 tons of lead are melted annually on Tyneside. Most of it is foreign pig-lead. During 1895 there were 250,000 tons of ore converted into pig-lead in this country. It is perhaps more to the poverty of silver in the native ore than to the cost of production of the raw material that the diminished output of recent years is to be ascribed. It hardly pays the proprietor to extract the silver when it is present in small quantity. English pig-lead contains a very small percentage of silver, seldom more than from 8 to 10 ounces to the ton. Foreign ores vary as regards the amount of silver held. In Spanish ore there may be as much silver as 40 to 80 ounces to the ton, and in Greek 80 ounces. Australian ores show very great variations. In some of the veins the ore contains 60 ounces to the ton, while in other samples there may be 500 ounces or even more.

So far as lead-mining in the North is concerned, the methods adopted for obtaining the ore are antiquated. Owners are apparently afraid to risk money in the enterprise, and as a consequence the means by which lead is mined are much inferior to those for getting coal. Lead mines, too, are not under the same Government regulations as collieries. Their ventilation is bad, the roadways are ill kept, and the mines are often damp, while the means of descent into, and ascent from, the mines, by a series of ladders, are arduous for the workers. So far as the mining of the ore is concerned, there is in this country practically no risk to the miner from lead poisoning, for he is dealing with almost a pure ore, viz., galena, which is a sulphide. Metallic lead is harmless compared with its compounds, the oxide and carbonate. It is this circumstance that explains why lead-miners at Broken Hill in Australia suffer so severely from colic and convulsions, while their confreres in England escape. The ore at Brocken Hill is very largely a carbonate. The English lead-miner runs the ordinary risks to life and limb from accidents, and in a special manner his health is endangered by pulmonary consumption and rheumatism, largely the result of exposure when returning from work heated and fatigued, also of the barrack system in vogue in certain places for housing the miners.

There is not much lead-mining carried on in France, but where it is there is freedom from plumbism among the miners as in our own country, with the exception of an outbreak of colic that occurred among the men who were working in the veins at Asprières (Aveyron), where the mineral was found, like the Australian ore, to be composed mostly of _cerusite_ or carbonate of lead. It is to a similar condition of the ore in the lead mines of Sierra de Gador that are attributed the 400 to 500 cases of colic annually observed by Dr Bayer among 12,000 miners--a malady to which the crushing of the cerusite in the dry state no doubt very largely contributes. (_Poisons Industriels_, Paris, 1901, p. 14.)

The dales of Durham in which lead-mining is carried on are sparsely populated: they are bleak, and swept by cold winds for the greater part of the year. In many instances the miners live a considerable distance from their work, and as railways have not yet penetrated into these remote corners of England, the men have to cover the ground on foot. Lead-miners are brought very little into touch with the outer world. They form a class by themselves, and cling with affection to their homes on the hillsides: they closely intermarry, and thus form not only one family socially but industrially as well. Their wages are small, seldom more than ten to twelve shillings a week, and yet, unless compelled through sheer necessity to renounce their badly paid and not too healthy occupation, they will not leave the district for the more lucrative work of coal-mining. As a class they are thrifty, intelligent, temperate, and religious. They are not long-lived. Pulmonary phthisis is extremely prevalent among lead-miners. In close proximity to some of the mines large “lodging shops” or “barracks” have been erected, where many of the workmen stay during the week. In one district, Dr William Robinson of Sunderland, formerly of Stanhope, found that 166 miners occupied one of these shops during three or four days and nights in the week. Often the barracks are in a filthy condition, for they are badly kept. As the sleeping accommodation is limited, the bedrooms are crowded to excess. In one room, 16 feet by 13½ and 9¾, there were 20 miners accommodated, _i.e._, at the rate of 124 cubic feet of air per man, while the model regulations of the Local Government Board require not less than 400. Most of the rooms have no fireplaces: the windows are fixed, and consequently there is no means of ventilation. As large numbers of men have to be accommodated, the beds are crowded together in two tiers 3 feet 6 inches from each other, so that there is barely space to pass between them. Since the rooms are occupied by different sets of miners working alternate shifts, the beds are hardly cooled before being again occupied, while in consequence of the air of the rooms not being renewed, the stench is overpowering. Bad as the sleeping accommodation is, the day rooms are not any better. The closet accommodation, too, is scanty and often badly placed. In his lodgings as well as at his work many a lead-miner is exposed to the influence of very unwholesome atmospheric conditions, the results of which are seen in his deteriorated constitution and diminished resistance to disease. The air of the lodging-shops is heavy with the effluvia from the bodies of their occupants. Sooner or later lead-miners suffer from asthma and pulmonary catarrh, the end of which is often tubercular consumption, and as the men expectorate upon the floors of the sleeping-room, the tubercle bacilli find in the badly-lit and ill-ventilated rooms the conditions which favour their multiplication. In this manner, and apart from his work, the lead-miner is brought under the influence of the microbe of pulmonary phthisis. The excessive amount of carbonic dioxide in the mines, the unconsumed products given off by the burning candles and those given off by explosion of gunpowder, render the atmosphere of the mine for the greater part of the twenty-four hours unhealthy. By the workman who lives a few miles from the mines, and who has to walk home across a bleak and wind-swept moor, tired and heated after a hard day’s work and wearing wet clothes, colds on the chest are readily caught and not readily got rid of. Out of these repeated pulmonary catarrhs consumption is prone to develop. Commencing work in the open air as a crusher and washer of ore, the son of a lead-miner--for the occupation is largely hereditary--will for health compare most favourably with any young artisan, but he has only to work a few years in the mine when he becomes short-winded. Once this defect is induced it gradually increases, and so at the age of forty to forty-five the lead-miner is old for his years: an asthmatic, he is the subject of wheezing cough and expectoration, and is often obliged to give up work entirely before the age of fifty. Life, however, may be prolonged for years, for the summer months bring abatement of the symptoms; the improvement, however, is only temporary, for the cold winds of winter and spring again light up the chest affection. Since in the mine the air is dusty, and the worker inhales particles of grit, pathological changes in the lungs are established similar to those mentioned in the chapter on Dust and Disease. The lung of one lead-miner that I have is almost solid from excess of fibrous tissue, and it feels as hard as stone, see Fig. 39. On microscopical examination the alveolar structure of the lung is found to be replaced by dense fibro-connective tissue. In the expectoration of some of the lead-miners I have found tubercle bacilli. The pulmonary disease of lead-miners, therefore, like that of workers in dusty trades, may be either a simple form of fibrotic phthisis due to inhalation of grit, or it may be a truly tubercular lesion grafted on to the less formidable fibrosis. The average age at death of lead-miners is about fifty. Nearly 50 per cent. of them die from chest diseases. In the dales around Stanhope, in the county of Durham, the death-rate from phthisis among a secluded population of lead-miners was 4.7, while in another part of the same Union composed of farmers it was only 0.6.

_Lead-smelting._

While the miners in this country do not suffer from lead poisoning, the same cannot be said of the men who smelt the ore. I have seen several smelters die from plumbism. In a few instances I have witnessed son after son in a family thus carried off before the age of thirty. The fume that escapes from the flue of the smelting shop contains oxide and sulphate of lead, and it is the inhalation of this that causes plumbism. Usually the lead fume is conducted into a long flue, 5 feet high and 3 feet wide; in some places the flue is carried up the side of a hill for a mile or two before it terminates in the chimney. This allows of the deposition from the fume of some of the oxide and sulphate of lead which is recoverable. At one large smelting works which I visited along with my colleagues on the White Lead Commission, we found that recovery of the deposited lead by men entering the flues was attended by such serious symptoms that we recommended two hours at a stretch as the maximum time for men to work in cleaning out the flues. Twenty cases of plumbism in lead-smelters were reported to the Home Office in 1900.

Although British galena contains usually but a very small quantity of silver, this can be profitably extracted when present in the ratio of even 2 of silver to 1000 of lead. Frequently the amount of silver present in foreign ores is so large that manufacturers prefer to extract the more valuable metal only. Desilvering of lead ore is generally carried out by the Pattinson process, introduced in 1829. Until that date silver was not extracted from galena. The ore had to be converted into an oxide in order to separate the silver, and the oxide resmelted to recover the lead, but unless the lead contained 8 to 11 ounces of silver to the ton it did not pay to extract it. While its removal has increased the production of silver, its extraction is by some authorities believed to have improved the quality of the lead. On the other hand it is stated that lead pipes made from desilverised ore are, when used for conveying drinking water into our houses, found to be too soft. They are more readily acted upon by water, and become consequently a more frequent cause of plumbism than the harder pipes made from British galena, from which the silver has not been extracted. The introduction of the Pattinson process has caused silver extraction to become a special industry. The process depends upon the formation of an eutectic alloy of silver and lead.[50] It is unnecessary to describe the Pattinson process, since it is detailed in all text-books on metallurgy and chemistry. Suffice it to say that the _desilvering_ plant usually contains five pots made of cast iron and set in masonry, and by a series of melting and skimming, cooling and transferring the separated silver and lead to a series of pots in succession, all the silver, practically speaking, can be removed from the lead. Although I have frequently examined men engaged in desilvering lead I have rarely found them the subjects of plumbism. Two cases of lead poisoning were reported to the Home Office in 1900 as having occurred in silver-smelters.

_Red Lead_; _Lead Oxide_; _Litharge_; _Massicot_;
_Minium_.

Lead oxide, the yellow and red, is got by melting metallic lead in a furnace exposed to atmospheric air. By means of a long iron rabble a workman keeps raking the molten liquid so that it is brought into intimate contact with the oxygen of the air. When removed from the furnace and cooled, the product assumes a red or yellowish colour according to the amount of oxygen it contains, and is known as the red oxide of lead and minium, or as massicot. During the operation of melting and raking the lead a certain amount of fume escapes from the open mouth of the furnace. The fume ought to be removed by a strong upward draught through a hooded chimney. Where this is not done and the men approach too near the mouth of the furnace, fume is inhaled, with the result that the workmen suffer from plumbism. A fairly large number of red-lead makers become anæmic and suffer from colic and wrist-drop. Great as is the risk run by the red-lead worker through inhaling the fumes from the molten metal, it is less than that incurred during the crushing and packing of the finished product. The substitution of mechanical agitation of the molten lead in the furnace for that done by hand by the workman would diminish the danger, since it would allow the doors of the furnace to be closed, except during the charging of the interior. The packing of casks with red lead should be conducted in closed spaces provided with a hood and such means as will create an effective draught. The workmen ought to wear overalls, have frequent baths, and be inspected at least every fortnight by a doctor. Men can work longer in red than in white lead without losing their health. There is no truth in the statement that they are _absolutely_ free from the severer forms of plumbism. As a rule, I have found the symptoms of lead poisoning in massicot makers on the average milder than those observed in white-lead workers; but the result depends upon the proximity and length of exposure to lead compounds rather than upon the particular nature of the compound itself--always, of course, remembering that the more soluble the lead compound the greater the danger. Some physicians have had quite other experience. Layet, for example, in a paper read before the Congress of Hygiene at Turin, 1880, stated that minium is more dangerous than white lead, and that the form of poisoning is just as severe, if not more so. He had found red-lead makers more liable to what is known as encephalopathy, _i.e._, the cerebral type of Saturnism, than white-lead workers.

_White Lead_; _Carbonate of Lead_ (_Céruse_, Fr.)

All the soluble salts of lead are capable of inducing plumbism, and of these the carbonate is perhaps the most prolific cause of lead poisoning. In Britain most of the white lead of commerce is made by the _old Dutch_ process. Thin sheets of metallic lead (wickets) are taken to the stacks or blue beds. The floor of the stack is covered by a layer of tan, and on the tan is arranged a series of earthenware pots containing dilute acetic acid. Upon the pots are placed the sheets of lead. Boards are laid over these, and thus the first layer is formed. Tan is thickly strewn over the boards, and when this has reached a sufficient thickness, other rows of pots partially filled with dilute acetic acid and covered over by thin sheets of lead are arranged on the tan, and the whole is covered over by boards. This second layer is followed by others similarly constructed, until by a succession of tiers the ceiling is reached, when the doorway is built up by boards and kept closed for a period varying from ten to fifteen weeks, during which the conversion of blue into white lead by corrosion takes place. The stacks are ventilated by means of a shaft at each corner. Once the “blue” beds are made up and the doorway closed, the tan begins to get warm and evolve carbonic acid. In consequence of this heat the acetic acid becomes volatilised, and through the interaction between the lead and acetic acid on the one hand, and the carbonic acid on the other, chemical changes of a nature not thoroughly understood occur, which ultimately end in the production of the basic carbonate of lead, or what is popularly known as white lead. When this conversion is believed by the manufacturer to have taken place, the stack is opened. It is then no longer spoken of as a “blue” but as a “white” bed. Workpeople enter the white bed to strip it of the corroded lead. What was originally placed in the blue bed as a thin layer of metallic lead has become converted, if the corrosion has been satisfactory, into a much thicker plate made up of a white crisp incrustation of lead carbonate, which often conceals from view very thin pieces of unaltered metallic lead. In stripping the white lead off the unchanged metal a considerable amount of dust is given off, the inhalation of which was previously much more frequently a cause of plumbism in the workpeople than now, owing to the fact that present regulations require that the white beds must be watered by means of a “rose.” The carbonate and unaltered lead removed from the white beds used formerly to be taken direct to the rollers, crushed and washed, so as to separate the two. After washing, the white lead is placed in earthenware vessels and taken to the stoves to be dried. The emptying or drawing of stoves has been the cause of a larger number of severe and fatal cases of lead poisoning than any other department in a white lead factory. Until 1898 the filling and emptying of stoves was very largely done by women, young and middle-aged, but the work was found to be so detrimental to female life that the White Lead Commission recommended that no woman or girl should be allowed to work in the stoves. I have known young women die from plumbism within three months after entering a white lead factory and working in the stoves. It takes from three to five days for the white lead to become thoroughly dried in the old form of stoves, after which it is packed into casks. Since the White Lead Commission published its Report there have been many improvements in stoves. There are many now in use which will tend still to diminish plumbism. In some factories wagons ladened with basins of moist white lead are run on rails into the drying chamber, while in others the white lead is made to fall mechanically on to a series of large revolving discs in a closed chamber heated by air. Packing is often a dusty and dangerous process if it is not conducted in a confined space ventilated by a shaft and fan. The white lead is mixed with oil and converted into paint. When visiting the white lead works in Paris of Messrs Expert-Besançon et Cie., a short while ago, I found that while the old Dutch method of manufacture was in use there was an immunity from plumbism among the employés that created a favourable impression upon me. That freedom I found was in the main due to the following circumstances: (1) no female labour was employed; (2) stoving was practically done away with; (3) the white lead was taken direct from the stacks to the rollers, where it was crushed and washed; then (4) passed through a series of rollers and mixed with oil, which gradually displaced the water,[51] so that a perfectly finished paint escaped from the last roller, practically free from, or containing only a very small percentage of water, and was passed automatically into casks, thus abolishing some of the dusty and dangerous processes as well as the handling of the white lead; (5) careful personal supervision of the workers, and attention to cleanliness; (6) regular medical inspection; and (7) alternation of employment. I reported to the Secretary of State upon these facts, with the result that they were laid before the white lead manufacturers of this country, many of whom adopted in a modified form the practice observed in Besançon’s works. English makers have since then informed me that it not only saves labour and therefore cheapens production (the product itself not suffering in quality), but has materially diminished the number of cases of lead poisoning in their factories.

White lead can be made by other methods. In what is known as the _chamber_ process strips of lead are suspended over parallel bars in a chamber, which is heated by steam, and into which carbonic acid is passed, while acetic acid is present in pans on the floor. The result is the same, viz., formation of white lead by a process of corrosion, only the conversion is much more rapid, being four or five weeks as against the ten to fifteen required by the stack process. The subsequent treatment of the white lead is the same in both cases. Much of the white lead manufactured in Germany is made by the chamber process, and in that country emptying the chamber is regarded as dangerous to health.

By the old Dutch process an excellent and very pure white lead is no doubt produced. The drawbacks to the method are that it is tedious, and that some parts of the process are extremely dusty, and therefore dangerous. There have been various attempts to manufacture lead carbonate by quicker methods, and of these the method of obtaining white lead by the action of acetic acid and glycerine upon the red oxide may be mentioned. In it the first step consists in reducing metallic lead to litharge by placing pig-lead in a furnace and allowing a jet of steam to play upon the vapour of the molten metal. The lead oxide is subsequently crushed into a fine powder. This, as I saw it, can be a very dusty and dangerous process. The red oxide is placed in large revolving barrels along with acetic acid and glycerine, and the churning is allowed to go on for about two hours. A greenish-white liquid is the result, and this is allowed to escape from the barrels into storage vats, from which it is conveyed into large cylinders called _carbonators_. Into these carbonating tanks carbonic dioxide obtained from burning coke and lime is conveyed, and the gas is allowed to bubble through the mass for about an hour, when carbonate or white lead is formed. After running off the supernatant liquid, the deposited lead carbonate is removed through pipes to the _presses_, where it is washed and any acetate that may cling to it is removed. After this it is taken to the stoves, into which it is run on a series of long narrow wagons, the workmen not entering the stove at all. By the third day it is sufficiently dried to be ready for packing or mixing with oil to make paint. This method of manufacture is known as the _precipitation_ process. In it there is no handling of the white lead until it reaches the presses. The dangerous parts of the process are: (1) the grinding of the lead oxide: this is dusty; (2) the pressing: in this the men handle the white lead, and as a consequence I have observed in young workmen marked anæmia, tremor of muscles, colic, and the presence of a deep blue line on the gums; and (3) filling the barrels with the finished white lead, when danger arises from inhalation of dust. In some works ammonia is substituted for glycerine. Conducted as an experiment, white lead manufactured on the lines just detailed is extremely satisfactory, but financially it is not very successful. Although the precipitation process is more rapid it is more costly, and as a consequence factory after factory which has adopted this method has been obliged to close.

In the manufacture of white lead by the _Bischof_ process the first stage consists, after converting metallic lead into litharge, in the reduction of the litharge to suboxide in gas-tight cylinders by means of water gas at a temperature of about 300° C. The suboxide is moistened in mechanical mixers with water, and converted into hydrate. By means of carbonic acid, dilute acetic acid and glycerine, the hydrate is converted into white lead in a gas-tight apparatus, and after separation of the liquid and washing of the sludge, the aqueous white lead is mixed with oil by mechanical means, and becoming thus ordinary white lead paint, it is packed ready for the market. No female labour is employed in the factory. The manufacture of white lead by the Bischof process at the time of writing is still to a large extent experimental, but it gives promise of commercial success. As the work is done by machinery, and is for the most part wet, there is no dust given off. The only possible unhealthy part of the process I observed was the mixing of the suboxide of lead with water, but where this is done mechanically, as I presume it can be in chambers provided with ventilating shafts, all danger can be averted.

In white lead factories the dangerous processes are emptying the white beds, washing the incompletely converted metallic lead plates, crushing, grinding, sifting, filling the pots with white lead for the stoves, emptying the stoves and packing the barrels with the dry white lead. It is the continual absorption into the body of very minute quantities of lead compounds either by the pulmonary or digestive tract that causes plumbism. The skin, too, offers another channel by which it may enter the system. Although it is usually in the form of dust that lead enters the body, it can also enter it in the form of fume, and possibly, too, mixed with steam in which the particles of lead are either dissolved or suspended.

Lead carbonate is an extremely fine white powder, and is largely sought after as a pigment by house painters, by plumbers for searing joints, and by pottery manufacturers for making the glazes in which the ware is dipped. As a pigment it is said by a large number of house decorators to be superior to any other. There is a decided preference in the trade, too, for that made by the stack process. It always commands a higher price, the reason being that it is believed to have much greater covering power than white lead made by some of the other processes. On account of white lead being such a dangerous product, both in its manufacture and manipulation, the question of finding a suitable substitute has often been raised. This subject was carefully gone into by the White Lead Committee a few years ago.

Zinc white, for example, was recommended, but the opinion come to was that while zinc oxide was practically free from the dangers incidental to lead carbonate, and answered well for internal decoration, for covering purposes and endurance in all kinds of weather there was no pigment equal to white lead. It is this widespread belief among house painters generally that makes white lead such a valuable commercial product.

The question of finding a substitute for white lead has not been confined to Britain alone. One hundred and twenty years ago, Courtois presented to the Academy of Dijon some zinc white, which was remarkable on account of its permanence, and in 1783 Guyton de Morveau recommended, from hygienic motives and on account of its chemical properties, zinc oxide for lead carbonate. Ten years ago a small representative committee reported to the Commission des Logements Insalubres of the city of Paris upon zinc white as a likely substitute. As far back as 1849 the Minister of Public Works ordered that all the Government buildings in France were to be painted with zinc oxide instead of lead carbonate, and although in 1852 the Minister of the Interior followed with a similar request to the various prefects, the resolution remained a dead letter. It was indicated to a fresh committee, appointed in 1891, that from an economic and industrial point of view, zinc white was inferior to white lead, that it had no great covering power, little durability, that it cost more, and that therefore the painting of State buildings by it would entail an unjustifiable expense. Some persons, on the other hand, held the belief that zinc white possessed just as good covering properties, so long as it was mixed with a larger proportion of oil and less of turpentine, and that the painter gave a sufficient amount of attention to his work so as to make the coating flat, also that it was not so readily blackened by sulphurous vapours. As for the increased expense, it was to be remembered that if zinc white costs more, it is also less heavy, and therefore weight for weight gives a larger body of material. The Commission, taking into consideration the hygiene of dwellings, the health of the workers, and the interest of landlords, and having the choice of two substances before it, of which one is almost harmless, and the other a strong poison, adopted the following resolutions: (1) the employment of zinc white to the exclusion of white lead will be specified in all the orders for painting; (2) the Commission renews the wish expressed in 1880 in regard to the exclusion of white lead in all public works. No special action followed these recommendations. Within the last few months the question has again been raised in France, and on this occasion more vigorously than before. The operative painters met in congress, and passed resolutions denouncing the use of lead in the manufacture of paint, and demanding that the law for compensation for accidents should be extended to include cases of plumbism. To the painters’ representatives the Minister of Commerce, at a personal interview, while admitting that the law on accidents was imperfect, stated that it was too soon to hope for its amendment. He undertook to do all he could to enforce the decree of 1849, that no more lead should be employed in painting and decorating State buildings. In France zinc sulphide, oxysulphide, and oxide have all been tried as substitutes for white lead, but although there is a belief that these can replace lead carbonate, there is an unwillingness on the part of architects and house-painters to discontinue the use of lead. In Britain other chemical compounds in addition to the above have been tried, _e.g._ sulphate of barium, but although this is a beautifully white substance, it does not mix so well with oil nor has it the covering power of white lead. The surface of the object painted can be seen through the coating of barium sulphate, a circumstance probably due to the fact that the barium salt exists in a more highly developed crystalline form than the lead compound.

In March 1901 the Comité Consultatif d’Hygiène of France reported upon this subject[52] that the manufacture of white lead has become less and less the harmful industry it was owing to the Expert-Besançon process of grinding and mixing the white lead in water, with the subsequent addition of oil as it passes through the rollers, careful medical examination of the workmen employed, and the removal from the works of those who seem to be susceptible to plumbism, or are inclined to the free use of alcohol. The Committee of Hygiene recognises that in house painters, want of cleanliness, also the excessive use of alcohol and absinthe, are responsible for much of the lead poisoning, and therefore, since it is impossible to regulate and control the habits of these men, they ought to be provided with paints which do not contain such an injurious substance as white lead. In zinc white the committee is of opinion that a proper substitute can be found for lead for most purposes. Many architects and builders still object to the use of zinc white, but there are many, on the other hand, who claim for it the same advantages as regards covering power and endurance, and who maintain that when exposed to sulphuretted vapour it forms a sulphide which is white compared with the black sulphide similarly obtained from lead. The zinc coating dries more slowly, and there is therefore some loss of time; the work of laying on, too, may be a little more difficult, and for polishing purposes zinc mastics do not harden so well. Zinc is not so good in calico-printing as white lead. There are some things therefore, the committee admits, that lead may be better for than zinc. It is also admitted that even zinc oxide may be accidentally contaminated by small quantities of arsenic and lead, also that it is slightly more expensive--for example, it costs 0.0152 franc more for each metre of work done. The committee concludes its report by stating that both in the manufacture of zinc white and in its application as a paint it is free from the dangers incidental to lead, and therefore it is worthy of a lengthened trial as forming the basis of colours for house painting, since there is a considerable amount of educated opinion to show that it can be substituted for white lead. The French Government is asked to set the example by having the public buildings painted with oxide of zinc.

No industry, unless, perhaps, it be that of pottery manufacture, has caused so much plumbism as the manufacture of white lead, and yet in none has strict attention to regulations and personal hygiene been so productive of good as in these two industries.[53] The bulk of the work is unskilled labour. In Newcastle and neighbourhood, until the last three years, most of the work in the dangerous processes was performed by women who led rather a casual life, and who took to the trade as a last resource, owing to the idleness, illness, or death of their parents or husbands. They were mostly of the poorest class, and were often ill-fed and ill-clad. After a few weeks or, at the most, a few months of pretty regular employment in a lead factory, particularly if much of the time was spent in stripping the white beds or emptying the stoves, young women would suffer severely from plumbism. As already stated, I have known young women who were strong and healthy when they entered a white lead factory, die from Saturnine poisoning within three months. In one instance a young woman had, to my knowledge, only worked forty days, spread over a period of nine weeks, when she succumbed to lead poisoning. I am firmly convinced that women, especially young women, are much more susceptible to plumbism than men. The predisposition to lead poisoning is in both sexes doubtless spread over all periods of life, but so far as occupation exposure to lead is concerned, my opinion is (1) that women are more susceptible than men; (2) that while female liability is greatest between the ages of eighteen and twenty-three years, that of men is later; and (3) that while females rapidly break down in health under the influence of lead, men can work a longer time in the factory without suffering, their resistance apparently being greater. In addition to a sexual predisposition to plumbism there is also an individual and a family tendency as well. It is difficult to explain this susceptibility of certain persons to lead poisoning. As to the fact, however, there is no doubt. It is partly a constitutional, and it may be partly a temporary and accidental condition. We find illustrations of constitutional predisposition to certain maladies in the greater liability of some people, for instance, to contract infectious diseases than others, in the readiness, for example, with which they catch typhoid fever and suffer severely from it. We have similar illustrations of the influence of age in the early years of adult life being those in which enteric fever is most severe. As an indication of how susceptibility to plumbism may be accidentally and temporarily developed, I would instance the influence of poverty, which, by preventing the purchase of wholesome and abundant food, allows the gastric juice probably to dissolve out more of the lead that has been swallowed. No doubt much of the greater prevalence of plumbism hitherto observed in women who have worked in white lead factories is to be explained by the fact that they have until recently worked in larger numbers than the men in the dangerous processes, for since June 1898, the date in which the Home Office required that male should replace female labour in these processes, the number of cases of plumbism in the men has increased, and correspondingly decreased among the women. Taking for example my own district, the number of cases of plumbism notified to the Home Office from Newcastle-upon-Tyne for the two six months’ periods preceding and succeeding June 1898, the date of the displacement of female by male labour, is as follows:--

NOTIFICATIONS. FATAL CASES.
Males. Females. Males. Females.
1st December 1897 to 31st May 1898 19 66 1 4
\ / \ /
\ / \ /
85 5
1st June to 30th November 1898 82 12 0 2
\ / \ /
\ / \ /
94 2

Between January and October 1898, Dr M. Legge states that there were received at the Home Office from certifying surgeons, 192 reports of plumbism. Of these the stoves supplied 76 patients and the white beds 31. The ages of the workers being--

Under 20 yrs. 20 to 30. 30 to 40. 40 to 50. 50 to 60. Over 60 yrs.
7 84 58 24 15 1

In three instances the patients had worked less than one week in the factory. In four-fifths of the total cases the lead poisoning took the form of colic, in the remaining one-fifth paralysis and cerebral symptoms.

Next to the susceptibility of women generally, and of young women in particular, I would say that all young adult life offers less resistance to plumbism than mature and middle age. In the House of Commons, 17th February 1898, the Home Secretary stated that there had been 37 cases of lead poisoning in factories and lead works among boys under eighteen years of age which had proved fatal.

Looking back upon the tables just presented, it will be observed that when males undertake the work hitherto discharged by females in white lead factories they develop plumbism in a ratio which might raise doubt in the mind of the reader as to the susceptibility of women to plumbism being greater than that of men. Admitting for the moment that the susceptibility is equal in the two sexes, and the fact, too, that in both the illness may be severe, still I unhesitatingly assert that in the main the symptoms are neither so severe in men, nor does the malady run so rapidly to a fatal termination as it does in women. In a word, females contract lead poisoning more readily, the symptoms are usually more acute, they suffer more severely, and they succumb to it more quickly than males. In women acute lead poisoning is more prone to assume the cerebral type than in men. We have, it is true, only the experience of the last three years to enable us to form an opinion as to the abolition of female labour in the dangerous processes of white lead manufacture having been a wise recommendation on the part of the White Lead Commission, but limited as the time is, the records of the Newcastle-upon-Tyne Royal Infirmary are not devoid of interest on this point.

LEAD POISONING.

_In-patients admitted into Royal Infirmary, Newcastle-upon-Tyne._

+------+--------+-------------------+--------------------+-----------+ |Year. | Total. | Recoveries. | Deaths. | Remaining | | | | | | on Books. | +------+--------+--------+----------+--------+-----------+-----------+ | | | Males. | Females. | Males. | Females. | | | 1892 | 44 | 15 | 27 | 2 | 1 | 2 | | 1893 | 32 | 5 | 25 | ... | ... | 2 | | 1894 | 31 | 7 | 20 | ... | ... | 4 | | 1895 | 35 | 11 | 18 | 1 | ... | 5 | | 1896 | 38 | 12 | 22 | ... | 2 | 2 | | 1897 | 21 | 7 | 12 | 1 | 1 | ... | | 1898 | 36 | 22 | 12 | ... | ... | 2 | | 1899 | 20 | 19 | 1 | ... | ... | ... | | 1900 | 14 | 14 | ... | ... | ... | ... | +------+--------+--------+----------+--------+-----------+-----------+

It will be observed that the number of deaths is equal for the
two sexes.

A decade ago the Newcastle Infirmary wards were scarcely ever clear of a case or two of lead poisoning. At present weeks or months may pass without one being in the wards. Beyond male labour having been substituted for that of females in the dangerous processes in the factories, and the circumstance that men are believed to do more work than women, I am not aware that there has been any reduction[54] in the number of people engaged in white lead manufacture on Tyneside that will explain the smaller number of cases of plumbism coming into the Infirmary, nor beyond the workhouses is there any other institution in this neighbourhood, other than the Royal Infirmary, to which patients suffering from plumbism could go. During 1898, the year in which men exchanged places with the women in the dangerous departments in white lead factories, the number of cases of plumbism admitted into the Infirmary was slightly greater than for one or two of the previous years, a circumstance possibly explained by the greater irregularity of work on the part both of the men and women, and the fact that the men were of a casual class and had not become accustomed to the work. Immediately after the abolition of female labour, not only is there observed a marked fall in the number of female admissions, but there is this astonishing feature, that while during 1900 only 14 cases, all males, were admitted, for the first time in the history of the Newcastle Infirmary within our memory a whole year passed without even one female being received. During the last three years, as also during 1893–1894, no death from acute lead poisoning took place in the Infirmary. There has been, too, a remarkable absence lately in the Newcastle daily press of announcements of coroner’s inquests having been held upon fatal cases of lead poisoning in the district compared with what there was a few years ago. Nothing could be stronger testimony to the wisdom of the Home Office in having enforced the recommendations than these facts. Although the manufacturers at the time strongly resisted the recommendation of the White Lead Committee, I believe they now admit that it was a proper step, also that work under the present system is better done than formerly, and that there is less sickness among the employés. The difficulty of substituting male for female labour, which manufacturers anticipated and which was their principal objection, has not been realised; the men do more work, and therefore the cost of production has not been increased, although wages have been higher; the men, too, are more cleanly. Improved methods of manufacture and diminished handling of products have doubtless contributed also to this satisfactory result. As the men have come to recognise the dangerous character of their occupation, and have made up their minds to follow it until they can get something better, they have become more careful, and therefore suffer less in proportion from plumbism. Casual work and irregularity of employment certainly play a not unimportant part in causing lead poisoning. The casual labourer is often ignorant and careless. As these pages are passing through the press, a man who had been stripping a white bed in a factory on Tyneside was found eating food with hands unwashed and covered with dust, while his face and beard showed only too plainly the presence of the same material. He stated that he had not been informed of any danger, and that no regulations had been read out to him. How easily, therefore, lead poisoning may be caused and almost as easily prevented. Dr Morison Legge found that of 1463 persons employed off and on in white lead works, the incidence of lead poisoning was 6 per cent. of the average number regularly employed, and in those with casual employment 39 per cent. Taking the whole number of hands passing through white lead factories in a year, the difference between these two, however, is less marked than at first appears, the numbers being 5 per cent. for the employed and 8.3 for the casual workers. Out of thirteen factories with regular employment four of them had no cases of plumbism to report at all, even although in one of these factories 110 persons were employed, whereas from two factories in which there was a large amount of casual employment 50 cases of plumbism were reported. The reasons why casual hands suffer more than those regularly employed are to be found in their carelessness and want of personal cleanliness, intemperate habits as regards alcohol, tobacco-chewing when at work, and unwillingness to wear respirators. During 1900 there were reported to the Home Office 356 cases of plumbism in white lead workers, but Dr Legge says, if two firms, one in Newcastle and the other in London, were excluded from the 18 firms, the total would fall to 175.