Oct. ist, lE 



■•] 



SCIENTIFIC NEWS. 



177 



the woodwork by fire ought to be enforced by law. We are 

 not sure, even, that the very bricks are sufficiently safe to 

 be used, as they often are, for building the internal walls of 

 houses. 



We come next to domestic animals of various kinds. Cows 

 are believed to be liable to a form of scarlet fever which 

 does not seem greatly to affect their own wellbeing, but which 

 is communicable, through their milk, to human subjects. 

 They are also liable to tubercular disease, especially when 

 aged, and the use of their milk, when in that condition, may 

 lead to pulmonary consumption. Cats are liable to diph- 

 theria, and may communicate this horrible disease to children 

 who play with them and receive their breath. Poultry and, 

 we believe, pigeons are subject to the same scourge. One 

 instance is on record of a canary-bird dying with evident 

 symptoms of scarlet fever. The most loathsome and intrac- 

 table of all known diseases, glanders, though it originates 

 among horses, is, unfortunately, capable of transference to 

 mankind. It is exceedingly imprudent to drink out of 

 any trough from which a horse can have been drink- 

 ing. 



We may remark that the penalty for leading or driving a 

 glandered horse along any public road is ridiculously trifling. 

 A drop of the secretion from the animal's nostrils blown by 

 the wind into the face of a passer-by may doom him to a 

 fearful death. 



But of all the unknown and disregarded channels of in- 

 fection the most powerful are certain insects — those, namely, 

 which beset us and creep upon our food and our persons. 

 These insects belong mainly to one group, the Diptera, or 

 two-winged flies. Of these, multitudes are at one moment 

 feasting upon the most repulsive substances, the carcases 

 of dead animals and morbid products, and the next we find 

 them settling upon our food. It has been ascertained that, 

 e.g., the common house-fly can and does swallow disease 

 germs, but these pass uninjured through its digestive organs, 

 and are deposited by it in places where they may prove 

 very dangerous. Thus by their agency infection is conveyed 

 from place to place. Still more noxious than the common 

 fly and its immediate kindred are the blood-suckers, gnats, 

 mosquitoes, sand-flies, etc., which positively inoculate us 

 with the poison of various diseases. In this manner mala- 

 rial fever, leprosy, malignant pustule, and probably yellow 

 fever are propagated. As regards malignant pustules, often 

 called carbuncle, the evidence is particularly clear. A man 

 finds himself bitten by a fly ; the bite does not heal, but 

 becomes more painful and angry. Suppuration follows, 

 and, unless very active measures are taken, constitutional 

 symptoms come on and often terminate fatally. The poison, 

 it must be understood, is not naturally peculiar to the insect 

 itself, but is derived from the remains of some animal which 

 has died of a kind of cattle-plague, and upon whose flesh 

 or blood the fly had been feeding. To bury such cattle is 

 no safeguard. Pasteur shows that the earth-worms work 

 up the infectious matter to the surface of the ground, and 

 when it has once arrived there it is distributed by flies. 

 This inoculation with carbuncle is more common in France 

 than with us, and the insects which effect it are familiarly 

 spoken of as inoiichcs charbonneiiscs, carbuncle flies. The 

 French have brought this evil upon themselves by destroy- 

 ing the small insectivorous birds. 



It is recommended that carrion of all sorts should not be 

 buried, but consigned to tanks of sulphuric acid. Here the 

 infectious matter will be infallibly destroyed, and the pro- 

 duct will be useful as manure. 'It is scarcely necessary to 

 say that animal refuse occurring on a small scale should be 

 consumed with fire, and that no cesspools, dung-hills, etc., 

 should be left without such a dose of disinfectants as may 

 render them unfit for the multiplication of flies. Stagnant 



pools, even the smallest, should be drained. We may pro- 

 tect our persons against most offensive insects by washing 

 with a good carbolic soap. 



EXTRACTION OF LIME FROM HIDES. 



A MOST important improvement in tanning has recently been 

 effected by Mr. E. Planta Nesbit, of South Australia, and has 

 been successfully proved in Bermondsey. It is, of course, well 

 known that the first step in tanning is to treat the hides with 

 caustic lime and water, for the purpose of loosening the hairs 

 — a process which requires, sometimes, weeks. The hairs and 

 the fleshy matter are then removed by scraping. The next point 

 is to get rid of the lime, which not only injures the quality 

 of the leather produced, but wastes the tanning material by 

 decomposing the tannin. For this purpose a variety of methods 

 have come into use, none of them thoroughly efficient. Some 

 kinds of hides, after having been well rinsed, are put into weak 

 or spent tan-liquors, and occasionally moved about. They are 

 then transferred to a stronger tan-liquor, and the same process 

 is repeated. But though this operation goes on for weeks or 

 even months, all the lime is never entirely removed. As a recent 

 authority says, " it hinders the ready penetration of the tan- 

 liquor and the perfect combination of tannin with the skins, and 

 so obstinately resists removal, that a portion is always found 

 in the best leather." 



In other classes of hides a most disgusting treatment is 

 adopted for the same purpose — the application of hate or pure. 

 This consists of the dung of do^s, fowls, pigeons, and sometimes 

 even of human excrement. In this loathsome compound the 

 skins are steeped for ten or fifteen minutes, and in some manner, 

 the theory of which is not fully understood, a portion of the 

 lime is removed. Sometimes, however, the whole mass, hides 

 and all, becomes putrid and is hopelessly ruined. We learn 

 that a firm of tanners in Australia lost in this manner ^^250 

 worth of hides in a single night. 



It is here that Mr. Nesbit's patent process comes in and effects, 

 in a couple of hours, the complete removal of the lime without loss, 

 injur}', or nuisance. The theory of the invention is as beauti- 

 fully simple as the practice is satisfactory. Carbonic acid gas, 

 if applied in sufficient excess, renders lime perfectly soluble in 

 water. Whether it exists in the state of slacked lime (calcium 

 hydroxide), or of chalk (calcium carbonate), the result is the 

 same. The hides, of whatever kind, are placed, as soon as they 

 have been scraped, in a vat of water, and carbonic acid gas is 

 forced in for about an hour. In this short time the lime is so 

 completely removed that neither the careful examination of 

 practical men, nor the refined methods of chemical analysis, can 

 detect a particle. 



Along with the lime there is removed a quantity of grease, etc., 

 which the workmen style "muck," and the hides and skins are 

 left clean and supple. 



Among tlie advantages secured are a great improvement in 

 colour, grain (saving one-third material and labour), great eco- 

 nomy of time, no breaking or cracking, and a velvet-like texture. 

 The cost of carbonic acid gas is merely nominal. An important 

 collateral benefit is that a tan-yard will cease to be a nuisance. 



The importance of this invention will be understood if we 

 remember that tanning in value ranks fourth among our national 

 nidustries. 



Ink to Wfute on Glass.— An ink that will write on 

 glass is made from ammonium fluoride dissolved in water, 

 and mixed with three times its weight of barium sulphate. 



The Twenty-four Hour Sysiem. — This system of 

 measuring time has been adopted on all the lines controlled 

 by the Canadian Pacific Railway Company. 



Strength of Snails. — It has been found that a snail 

 weighing one-quarter of an ounce can drag up vertically a 

 load of two ounces and a quarter. Another snail one-third 

 of an ounce in weight carried horizontally a weight of 

 seventeen ounces. 



