excess of carbonic acid, but ladened with micro-organisms, which are believed to play an important part in the causation of consumption. No wonder therefore that we learn of pulmonary diseases, acute and chronic, being the lot of the lead miner. They shadow him at his work in the mine, in the lodging shop when asleep, and in the long, cold walk across the moor.

Lead

Setting aside these risks, it may be repeated that the lead miner in this country never suffers from plumbism. There are fewer men engaged in the mines to-day than formerly. Many of the lead mines in the North of England are closed and have been for years. The importation of lead from Spain and Australia, richer in silver and thrown cheaply into the English market, has largely lessened the output of native ore. mining is with us therefore a declining industry. Foreign competition has practically strangled it. Whilst the lead mines in this country are free from saturnine poisoning it must not be inferred that this holds good all the world over. In the Report presented to the New South Wales Government by a committee appointed to enquire into the prevalence and prevention of lead poisoning at the Broken Hill Silver Lead Mines, it is clearly demonstrated that several of the miners have suffered from plumbism; also that whilst the getting and working of the ores composed of sulphide of lead or galena are attended with little risk to health, those that contain carbonate are dangerous, a danger that increases in proportion to their friability and dustiness.

I have always maintained that the special dangers incidental to the manipulation of lead are not met with in the getting, but commence with the smelting of the ore. Smelting of the metal is not a large industry in this country. It is an occupation attended by a certain amount of risk. Lead is volatile at high temperatures. Inhalation of the fumes of the molten metal by the smelter was in days gone by a frequent source of poisoning. In one instance that came under my own observation four sons in one family-all strong healthy men-died at an early age, under 30, from chronic lead poisoning. At present the risk to the smelter is practically nil. Owing to the hood which is placed in front of the furnace, the draught carries the fumes all up the chimney. Lead smelting can scarcely be regarded therefore as a dangerous occupation. It is absolutely necessary however that the chimney stalk should be high, so that the fumes may be widely dispersed by the wind. The lighter dust thus floats away, and is carried a great distance, but the heavier particles necessarily fall close at hand, and become a source of danger. Cattle grazing in the fields near lead smelting works have suffered from colic-they are said to be "bellond," an old

French word, the interpretation of which is briefly" bellybound." Horses, sheep, and oxen, that have eaten of the contaminated herbage have died, and, in the processes of litigation that followed, farmers have succeeded in obtaining compensation from the factory owners for the damage thus inflicted upon their flocks. In Germany an interesting circumstance was noticed by Schroeder and Reuss. In close proximity to some of the forges they noticed that the red berries of the mountain ash trees were regarded as a favourite food by the thrushes and finches in the autumn, as well as by nearly all the birds that remain there over the winter. Below and close to these trees they often picked up birds sickly or dead. Those that were alive had their extremities contracted, and their power of flight appeared to be paralysed. Some of them died in a few days, powerless in their attempt to flutter. The birds had eaten the berries upon which were deposited the particles of oxide of lead, and had thus poisoned themselves. Plumbism was not confined to the small birds, for the wild animals that roamed in the woods close by also suffered from paralysis, the stags amongst other things exhibiting a peculiar defect in their antlers. On meadow hay taken from the neighbourhood of the Altenan forges, Freytag found a deposit of lead oxide equal to 0027

per cent.

I have alluded to the Broken Hill Mines. As illustrating the poisonous nature of the fumes emitted from their chimneys, I need only mention that a child aged five years died from lead poisoning. She had been in the habit of plucking flowers and putting them in her mouth, the flowers bearing visible particles of flue dust which had fallen upon them from the smelter stack under the shadow of which she resided. Cows, horses, dogs, and fowls died close to the mines. The soil surface on being analysed was found to contain a percentage of metallic lead varying from 05 to 481. In my own neighbourhood I have known dogs that had slept upon the jackets of their masters when engaged in the smelting shops, licking the sweet dust or that had lapped the water trickling from lead works, suffer from colic or exhibit a peculiar form of nerve symptoms due to the effect of lead upon their brain. Wherever lead smelting is carried on to any extent, there is a risk of the pasturage becoming contaminated. Whilst the risk to the smelter has been greatly diminished by the hood placed in front of the furnace, nearly all the men thus engaged are pale and exhibit a well-marked blue line along the margin of their gums. One danger however still remains, and that resides in the flue itself. The smoke that issues from the chimney of a smelting furnace is composed of two parts, one the ordinary fume from the

metallic vapour arising from the molten metal and mixed with atmospheric air, and the other the heavier part or flue dust in which lead is sometimes present to the extent of 20 or 40 per cent. These flues have to be cleaned out, and in some instances men have told me when thus engaged they have been obliged to come out, suffering from dizziness and a splitting headache, and have vomited freely.

English pig lead contains very little silver-seldom more than eight or ten ounces to the ton-so that it does not pay the manufacturer to extract it. In the Spanish lead there is from forty to eighty ounces to the ton, and in the Greek eighty ounces, whilst in the Australian metal the silver is very variable. It may be as low as sixty ounces to the ton or it may range from 400 to 500 ounces, and in some exceptional instances I am told it may run 1,000 ounces to the ton. Under these circumstances the silver is worth extracting from the lead, and on Tyneside desilverization is largely carried on, so that we send to the mint and the buyers in London several tons (upwards of fifty tons) of silver every year. The silver may be extracted by what is known as the Zinc or Parkes' process, the principle of which depends upon the fact that when silver-lead ore and zinc are melted together at a suitable temperature and allowed to cool slowly, the zinc alloys itself with the silver and rises with it as a crust which floats on the molten mass and can be skimmed off from it. By repeatedly melting and concentrating these rich crusts, and the adoption of certain processes to recover the zinc, it is easy to obtain pure silver. Workmen employed in desilverizing do not appear to suffer. I have never known of a case of lead poisioning amongst them. In all the works that I have visited I have always found the men thus employed very healthy, well developed, good specimens of the British working

man.

The manufacture of red lead is an easy, and on the whole not a very harmful, process. Pig lead is placed in a furnace, and when molten a workman keeps stirring the mass by means of a long iron rake. By degrees the metal becomes oxidized, and is removed from the furnace as a yellow powder, known as Massicot. This is subsequently returned to the furnace, and again raked up and down so as to allow of its complete oxidation. When this is accomplished it is drawn out, and it is noticed that the yellow colour of the Massicot has been replaced by one of a dark raspberry red. This on cooling and on exposure to the air gradually assumes the colour of the ordinary red lead of commerce. It is an oxide of lead, and in its manufacture, whilst we admit that the work is hard-something of the nature of the puddling of iron, though not so severe-any

danger to the individual from lead poisoning is minimised by the free ventilation in front of the furnace, and by the draught carrying away all the fumes. The danger arises when the manufactured article is removed from the furnace. It is a coloured powder, and as the heat at which it is drawn off is considerable, there is naturally given off a certain amount of fume, and later on, red dust. When a sunbeam slants through one of these shops you can see the red particles floating in the atmosphere. As the dried red lead is frequently packed into casks in the same part of the factory where it is manufactured, there is disseminated a large quantity of dust through the air, inhalation of which may cause colic. Colic and wristdrop, or paralysis of the hands, occurs amongst red lead workers, and are due to inhalation of an atmosphere charged with red lead dust. Careful attention to the raking-out of the furnaces and the packing of the dried red lead in closed chambers, along with scrupulous cleanliness on the part of the workmen, would tend still further to diminish risks to health.

So far as we have gone it cannot be said that lead making is a very dangerous employment to the individual engaged in it. When we come to consider the manufacture of white lead, we observe that at certain stages of the process a good deal of dust is evolved. It is the inhalation of this fine penetrable dust, and the fact that women are largely employed in the trade, that have gained for this industry a bad name. We believe that

women are much more susceptible to the influence of lead than men. This statement, for which I am largely responsible, has been disputed, but an increasing acquaintance with the subject, an extensive hospital experience of plumbism, and renewed experimental investigation upon animals, lend weight to the opinion that women are not only more susceptible than men but they are so at an earlier age. In addition there is a greater tendency for lead poisoning to assume its most serious form, in which headache followed by convulsions and coma are the most prominent symptions. Such an illness is frequently fatal within three days after its development. It is because several young females engaged in the white lead works have died rather suddenly, that the Home Secretary, influenced by public opinion, nominated a few months ago a commission to enquire as to how far their fatal illness could be attributed to the special nature of their employment and how far it is preventible.

White lead is made in considerable quantity in this country. On Tyneside alone the annual out-put is about 15,000 tons, and were trade good, there is a productive capacity for two or three thousand tons more. English white lead has to compete with that of foreign manufacture, and were it simply a question of

L

quality, e.g., purity of colour, covering power and durability, educated opinion would at once decide in favour of the homemade article. No method of manufacture can touch that which is generally in use in this country and which is known as the old Dutch process. There are two other, the "chamber" and "precipitation" processes. On the Continent white lead is largely made by the precipitation process, but the quality of the article produced does not compare favourably with ours. The Dutch method has long been in use in this country. Thin sheets of metallic lead placed in a chamber spoken of as the "blue bed," are exposed to the vapour arising from acetic acid. The acetate of lead so formed becomes the subacetate, and is subsequently converted into carbonate of lead from the carbonic acid arising from the tan in which the jars containing the acid are deposited.

After describing the Dutch method the lecturer said, so far as this process is concerned the first element of danger to health arises when the metallic lead is converted into carbonate. This occurs in what is known as the "white bed." Manufacturers generally allow thirteen weeks for this process to be accomplished. It is believed by some that if the conversion of the acetate into carbonate is incomplete, and the stack or "white bed" is opened too soon, that the girls sent in to strip it suffer more from headache than on other occasions, owing to the acetate of lead floating in the air with carbonate being a finer dust and more soluble, and therefore more readily absorbed than the pure carbonate. It is advisable that the stack should not be opened too soon, that when stripping a "white bed" the surface should be sprinkled with water, and that those who are stripping, but not those who are carrying the white lead, should wear respirators. No respirators, however, can keep out all the dust. They are certainly preventives. Without them a larger quantity of fine lead dust would doubtless be inhaled, but they are not an absolute protection.

It is after the white lead has been washed and ground and the wet pulp placed in the stoves for a few days that the principal danger arises. It is the drawing or emptying of the stoves that tells hardest upon the girls. A few hours in the stoves every week may, if excessive care is not taken, very quickly develop symptoms of saturnine poisoning. The wearing of overalls and respirators, careful cleansing of the hands and teeth before eating, a good meal before starting the work of the day and a bath at the end of it, and only one day's work a week in the stoves are precautionary measures, the value of which cannot be over-rated. A better procedure, however, would be the abolition of the present stove or drying chamber and the substitution for it of one that could be filled and emptied mechanically.