I thought that while there was life there was hope, and I determined to do more than anybody had done before; where one man had used a hundredweight of lime I determined to use a ton, and where one man had used a pint of carbolic acid I determined to use a gallon. The dry substance I had at hand to deal with in large quantities was lime. This I slaked in small pyramids in the centre of the sheds; I also laid trains of it outside the sheds

underneath the ventilators, and then slaked it. I also smothered the roads and paths at different points in layers of quicklime, three or four inches deep, so that every man and animal would be compelled to pass it. After scouring out the sheds, every cow's tail was dipped into a bucket of carbolic acid and water. Their heads and noses were dabbed over with it, also their sides and flanks. All the manure and litter from the cow's stall, as well as from the adjoining ones, was taken out at once, and the floor thoroughly cleansed and saturated with carbolic acid; and on the suggestion of Professor Brown I had four days previously commenced the use of sawdust saturated with carbolic acid, one or two shovelfuls of which were placed every day underneath the cow's head. This operation was also repeated in each stall, and the cows were then drenched with gruel

and sulphite of soda.

He then adds

Of the fifty-eight cows in shed F. and fifty-three in shed E, that I took the entire charge of, and treated as described, I did not lose one. Two that had been condemned to death were "smuggled " out, and exchanged for two others of less value. These two condemned had been in actual contact with diseased animals in every stage of the disease, in no less than three infected, and highly-infected, sheds, and were even placed beside a diseased animal in a shed which

had been emptied of diseased animals suffering from the most virulent type of the disease for a couple of days, and had only been disinfected for thirty-six

hours.

Poisoning by Carbolic Acid.-There have been numerous cases of poisoning by this acid;

in most cases it has been taken in mistake for

medicine. The symptoms are, in the recorded cases, great prostration, inability to swallow, pain in the stomach and throat, black stools and dark urine, speechlessness, coma, weak pulse, and death.

Death usually takes place quickly. A young married woman, after taking about 7 oz., died without a struggle almost immediately. A child æt. 7, after taking an ounce, died * comatose in 1 hour and 15 minutes. Another case died † in three-quarters of an hour after taking an ounce. But sometimes death takes place a

enough, the action of the acid was limited to three feet of the small intestine, the whole of the canal, from the lips to the first two inches of the duodenum, escaping unhurt. In some cases, Dr. Moxon has witnessed a kind of tanning of the stomach; and in a case that Dr. Way brought before the Pathological Society,

the mucous membrane of the stomach and the intestine for fifty inches was thickened and altered, and of a bluish-white colour. In all cases the odour of the acid has been distinctly perceived in the stomach, sometimes in the brain, and often in the urine.

Treatment.-The best treatment appears to be the prompt administration of bland oils, such as castor or sweet oil, in cases of poisoning; but unfortunately the action appears so rapid that, before assistance arrives, the case has gone too far. Besides, in most cases the power of swallowing is gone, and the stomachpump is more likely to do harm than good. In the recorded cases, oil, gruel, brandy, and emetics appear to have been given with but little effect. There is generally great depression of temBrandy should be avoided. perature, which should be kept up by artificial means. If the dose of acid is large, under any known treatment the patient will probably die.

Tests. The tests for carbolic acid have often failed, even when it has been smelt strongly in the animal fluids.

The odour is, therefore, in cases of poisoning, the most reliable. The following are some other tests: A slip of deal, as already mentioned, dipped in carbolic acid, then moistened becomes of a bright blue colour. with nitric or hydrochloric acid and dried,

Perchloride of iron added to carbolic acid

gives a beautiful mauve or purple colour.

tube, a little saliva added, and then a few A small quantity of the acid put in a testdrops of tincture of guaiacum, allowed to stand exposed to the air, then shaken, becomes of a bottle-green colour.

little chlorimated lime has been added, and A weak solution of carbolic acid, to which a then liquor ammonia, shows a bright blue colour.

Carbolic acid may be distinguished from creosote by its solubility in glycerine. Creosote is insoluble in glycerine. See DISINFECTION, &c.

Acid, Carbonic - This acid is considered partly in the article AIR, in which it is always present in minute quantity. Indeed its presence is essential to vegetation. Besides the sources of respiration and combustion, it issues in a comparatively pure state from the earth in various places, e.g., the Grotto del Cane, in Italy, and the Valley of Poison, in Java. It is also to be found in all springs, and it gives to them their sparkling character. In a solid state it is combined with various constituents of the earth's crust, as limestone, magnesia, &c.

Its properties are well known. It is a colourless, uninflammable, irrespirable gas, having a slight pungent odour and feebly acid taste. Its chemical formula is CO2; its equivalent is 44; its relative weight, 22; and specific gravity, 1.5203. It may be liquefied by pressure and cold, or, in a simpler manner, by generating it in closed strong vessels. It then forms a liquid as transparent as water, requiring a pressure of 385 atmospheres to retain it in the fluid state; and when allowed to escape into the air, freezes, from the rapid

evaporation, into a snow-white solid. Its most

marked properties are its weight and power of extinguishing both flame and life. 100 cubic inches of it weigh, at 60° F. and 30° Bar., 47.303 grains. It may therefore be poured from one vessel to another like water, and it collects at the bottom of vessels, vats, mines, or other places where it is developed or introduced. An atmosphere containing one part of carbonic acid in 2500 acts upon the system like a narcotic poison.

The tests and estimation of carbonic acid in air are described under that article. For carbonic acid in spring water, see WATER, ANALYSIS OF.

When combined with bases in the numerous carbonates, the following method is generally employed: Two flasks (the size and weight of which must be regulated by the capacity of the operator's balance) are connected as in the diagram. The weighed substance put into a, the other one, b, is half filled with concentrated sulphuric acid. The tube e is closed by a little bit of indiarubber tubing drawn over it, and a small, accurately-fitting bit of glass rod inserted in the open end. When all is ready, the apparatus is accurately weighed, the glass rod removed, and by sucking at e, successive portions of acid are made to pass over from b. The carbonic anhydride escapes perfectly dried through d. At the end of the operation the stopper is removed out of a,

indicates the carbonic acid. This process is not so suitable for bases which form insoluble salts with sulphuric acid, and in that case is modified by having a bulb on a, containing dilute nitric acid, which is allowed to escape from time to time on to the substance in a.

There are various other contrivances based upon the apparatus as above described; but the principle is the same, and it would be out of place here to go into more detail. Another

acid is by fusion of the previously dried and weighed carbonate with vitrified borax, also previously weighed. The loss of weight indicates very accurately the carbonic acid.

very convenient method of estimating carbonic

In cases of poisoning by this gas, the treatment of the drowned will be required, viz., artificial respiration, ammonia to the nostrils, free exposure to air, and galvanism.

Acid, Citric-See CITRIC ACID.

Acidimetry-This is the name of chemical processes by which the amount of free acid in any liquid is determined. It is of great use in the arts, as well as to the food analyst, who by it determines the amount of acid in beer, wine, &c. If the liquid contains a free acid, and is not mixed with anything else but water, the specific gravity may be taken in the ordinary way, or determined by a hydrometer; the percentage of acid will then be found by the aid of the following tables :

TABLE showing the Percentages of Crystallised Acid corresponding to various specific gravities of Aqueous Tartaric Acid, by OSANN.

Specific Gravity. 1274

1-208

1174

1-155

1-122

1-109

1968

1-023 1005

Percentage of Crystallised Acid.

51.42

40.00

34.24

30.76

25.00 22-27 14-28 5.00 1.63

The more generally useful method is, however, to prepare an alkaline fluid of known strength, and neutralise the acid. In order to do this, the operator requires burettes, tincture of litmus, or litmus paper, a dilute acid of known strength, and a dilute alkaline fluid also of known strength. The acid solution must in all cases be diluted so as to contain an exact equivalent number in grammes or grains of the acid in 1000 c. c. or parts. For instance, 40 grammes of sulphuric, 36 46 of hydrochlorie, 63 of oxalic to the litre. These solutions are called normal acids.

The normal alkaline solution is made so that one volume of it exactly neutralises one volume of the acid solution. Soda is nearly always used. In order to prepare it, a solution of soda is made, and diluted until about the specific gravity 1'05, which corresponds to 3'6 per cent. of soda. A portion of it is then run from a burette, until it exactly neutralises 30 c. c. of a normal acid solution. The exact point of neutrality is determined by litmus. Suppose 27 c. c. of soda neutralises 30 of the acid, then it is too strong; to every 27 c. c. 3 c. c. of water must be added-i.e., 111·1 to the litre.

The solutions of normal acid must be prepared with great care; the acids used must be absolutely pure. A solution of oxalic acid Fresenius does not think so good for acidimetry as hydrochloric acid, on account of the difficulties in drying the former. (See ACID, OXALIC.) The normal hydrochloric acid is thus prepared :-900 c. c. of water are mixed with 180 c. c. of ordinary pure hydrochloric acid of 1.12 specific gravity. Fill a burette with the mixture, measure off two quantities of 20 c. c. each, precipitate the acid with nitrate of silver, carefully filter, dry, ignite, and weigh the resulting precipitate: the two precipitates should agree very closely. Take the mean of them, and calculate from them how much water must be added to 1000 c. c. E.g., suppose 20 c. c. contained 810 grammes of hydrochloric acid, therefore 1000 c. c. contains 40.5 grammes, consequently we have

36-46 : 1000 : : 40.5 : x

-1110-8

Hence 1110.8 must be added to the litre of water. Normal sulphuric acid is prepared on a similar plan, only it is precipitated by chloride of barium. (The resulting sulphate, if multiplied by 34335, gives the sulphuric acid.) The actual analysis is performed by taking a determinate quantity, say 100 c. c., of the liquid to be examined, and dropping from a burette the alkaline liquid until exact neutrality, as determined by litmus paper or tincture of litmus, and the number of centimetres used will indicate the amount of free acid.

The following table will be found useful: