Old grass meadows and pastures receive much serving animal and vegetable substances and damage in the winter. As Disinfectants. -All the mineral acids are powerful if poured upon putrid matter, because they destroy it; but they are hardly suitable for common use, on account of their irritating nature to man. In 1773 Guyton Morveau wrote a large volume recommending muriatic acid as a disinfectant, and Dr. Carmichael Smith used nitrous acid at Winchester in 1789. Sulphurous acid is of real value, and has been used from the most ancient times as a disinfectant and fumigator. (See SULPHUR.) Of the organic acids, vinegar, or impure acetic acid, still deservedly retains some repute as a disinfectant; yet it is only a weak agent, at all events a poor protection against the germs of disease, for in vinegar itself infusoria and vegetable organisms develop. Most stinks are in all probability compound ammonias, at all events the odorous gases of this nature usually have an alkaline reaction; therefore vinegar or other acid fumes probably neutralise them. The most valuable of the acid disinfectants are, however, carbolic and tar acids. The acids that have been used accidentally or designedly as poisons are sulphuric, hy drochloric, nitric, arsenic, and phosphoric among the mineral; oxalic, meconic, prussic, and a few others, among the organic acids. The most important of these will be considered under their respective heads. The antidotes for poisoning by the mineral acids are chalk, magnesia, white of egg, oil, &c. anatomical preparations; it is also much employed in the arts, manufactures, and for medicinal and other purposes. Acid, Benzoic-(HC,H,O)—This acid is usually obtained by subliming it from gum benzoin; occasionally by dissolving it out from the gum by means of an alkaline liquid. Its principal adulterations are-hippuric acid, detected by its diminished solubility in water (1 part of pure benzoic acid is soluble in 300 of water), by its exhaling the odour first of the tonquin bean, and then of prussic acid; succinic acid, recognised by the solubility being increased; sugar, detected by the odour of caramel, and the black and carbonaceous residue-while pure benzoic acid sublimes. Camphor and spermaceti are also used, and may be detected by the odour, and other well-known properties. Acid, Caffeic-According to Vlaanderen and Mulder, the formula for this acid is C14H6O7. It is an astringent principle obtained from coffee. The dry berry contains about 5 per cent. of it. 14 Acid, Camphoric (H2C10H10 ̧) — Obtained from the oxidation of camphor by nitric acid. See CAMPHOR. Acid, Carbolic (Phenic Acid), (Phenylic Acid) - (HC,H,O.) - Sp. gr. of (35° C.); boiling-point, 369° (187° C.) This liquid, 1065; fusing-point about 95° F. substance, when pure, is in crystals in the form of long, colourless needles. It is obtained from coal tar. The commercial acid is, roughly speaking, of two kinds : one a cheap liquid, varying from a light-brown to a very dark, almost black, liquid; and Calvert's carbolic acid, which is in beautiful white crystals, and is used for medicinal and other purposes. Acid, Acetic (HC,H ̧O2)-Sp. gr. Properties.-The crystals, when pure, are 1063. This acid derives its name from white; but in keeping frequently become pink, acetum, vinegar. It exists naturally in the sap rose, or crimson. It has a powerful tarry of the oak, and in other plants. It is usually odour, and a very small quantity of water obtained from the destructive distillation of serves for its liquefaction. The crystals are wood, or from the oxidation of alcohol. (See very sparingly dissolved in water, but they VINEGAR.) The acid is often adulterated with are freely soluble in alcohol, acetic acid, and water, sometimes sulphuric acid and lead-1ether. With bases the acid forms phen ates or carbolates potash, &c. A slip of deal moistened with carbolic acid, and then dipped into hydrochloric or nitric acid, turns in drying to a blue colour. e.g., carbolates of lime, is of inestimable value. Mr. Crookes investigated it with great industry, and found that a solution of 1 per cent. preserved meat, skin, gut, and other substances if steeped in the solution and then dried; it also stopped fermentation, and destroyed gnats, beetles, caterpillars, mites, fish, and infusoria. A drop of the acid leaves a greasy stain on paper, which is, however, transient. Solutions of the acid do not redden litmus paper. The most important properties of carbolic acid are its disinfectant and antiseptic powers. Of late years it has taken its position in popular estimation as the best practical deodoriser and disinfectant for drains, putrefying matter, &c. &c.; and as a preventive of disease it has been placed in nearly all the urinals and waterclosets of railway stations, in the hospitals, barracks, and other public places in the kingdom. It is invariably used in all kinds of contagious diseases to disinfect the excreta, and in a diluted form is frequently applied direct to the bodies of persons suffering from smallpox, scarlet fever, &c. Nor has its use been confined to this country. Angus Smith has recommended it for the disinfection of sewers. M'Dougall has used a mixture of tar oil and lime for this purpose in Carlisle; and in Leipzig a mixture of chloride of magnesium, lime, and tar has been tried, and found of some practical value. The two principal carbolic acid powders in use here for various purposes are M'Dougall's and Calvert's. M'Dougall's powder is composed of Carbolate of lime, 33 59 8 100 Calvert's powder consists of carbolic acid In France, M. Devergie has warmly supported (20 to 30 per cent.), alumina, and silica. it, and declared it to be the best disinfectant known. He has employed it successfully in purifying the Morgue. This is done by a continuous stream of carbolised water, containing 1 of the acid to 4000 parts of water. That it is extremely valuable for these several purposes it is impossible to doubt; that it is superior to every other disinfectant, as some have asserted, may well be questioned. One of the gravest objections is its poisonous character. It is obvious that it is unsafe to drench and saturate all sorts of places with such an active poison as carbolic acid. It certainly does not destroy when in a dilute form every form of contagion. Dr. H. J. Von Ankum, in the "Morandschrift voor Natuurwetenschappen," states that atmospheric air, to which the vapour of carbolic acid has been added, does not hinder the development of lower organisms in water with hay in milk or urine. Experiments have also been made with air saturated with carbolic acid on vaccine lymph, which has, after exposure to this agent for some time, still preserved its activity. This agrees with Pettenkofer's observation,* that carbolic acid preserves inert ferment cells, but they resume their activity upon withdrawal from its influence. In fact, its real action appears to be very similar to that of great cold, the substances are preserved as if frozen. On this account it must be looked upon with suspicion as a disinfectant when any contagious germs are to be dealt with; it may fix them for a time, but does it destroy them? On the other hand, as an antiseptic it * Allgemeine Zeitung, Feb. 4, 1866. These powders may be sprinkled about a room, added to sewage, or diffused in water, and applied in solution. In disinfecting cholera or typhoid stools, See very strong solutions should be used. DISINFECTANTS. cerine is a good application to make to the One part dissolved in 100 of olive oil or glybodies of patients suffering from smallpox, scarlet fever, or other disease in which cells or germs are supposed to be thrown off. It is used as a medicine both topically and internally-topically, as an application to the skin in the strong form as an escharotic; and diluted, as a lotion to all kinds of foul sores, skin diseases, &c. Internally it closely resembles creosote in its action, allays vomiting, and is said to be useful in diabetes. During the prevalence of the cattle plague it was extensively used. The appendix to the Royal Commissioners Report on the Cattle Plague contains the following: According to the principles laid down, the air must be treated, and where there is no disease there is only a secondary use in treating anything besides the air. Several cowhouses have been treated with carbolic acid with very excellent results. The mode has been, first, to remove from the floor the mass of manure which too often adheres to it; secondly, to sprinkle the floor with strong carbolic or cresylic acid; next, to wash the walls, beams, and rafters, and all that is visible in the cowhouse, with lime, in which is put some carbolic acid, 1 to 50 of the water used, or with strong carbolic acid alone. Next, to make a solution, containing 1 of carbolic or cresylic acid to 100 of water, or perhaps still better, 60 of water, and to water the yard and fold until the who place smells strongly of the acid. Only a few farms have been treated in this way, so far as I know, but in each it has been successful. It may be well to give the cattle a little of the weak solution of carbolic acid, but this has not been so fully tried as the external use. The washing of the mouth and entire animal with the weak solution may be attended with good results, especially in the early stage of disease; but I know nothing of cure, and speak only hopefully of prevention. The animals seem to have an instinct for disinfection, and lick substances touched with this acid. They must not be allowed to drink it, as when strong, as already said, it blisters the skin, and especially the mouth and tongue. Mr. Crookes gives the results of his experiences as follows: It appeared evident that if harm were to follow the injection of carbolic acid, the mischievous effect would be immediate; but that if the fluid could pass through the heart without exerting its paralysing action on that organ, and could get into the circulation, no present ill effects need be anticipated. I therefore determined to push these experiments as far as possible, increasing the quantity of carbolic acid until it produced a fatal result. The next operation was on cow No. 11, in which 8 ounces of solution (containing 52 grains of pure carbolic acid) were very slowly injected: no bad effect followed. Increasing the dose, cow No. 12 had injected into her vein 4 ounces of solution (equal to 78 grains of carbolic acid); this also was followed by no immediate ill effect. Cow No. 13 was then treated with 6 ounces of solution (containing 105 grains of pure carbolic acid), in two portions of 3 ounces each, five minutes' interval elapsing between each injection. The first 3 ounces produced a slight trembling, but not so severe as in the case of cow No. 10, as she seemed better in a few minutes. The second dose of 3 ounces was injected. This proved too much, or was pumped in too hurriedly; for almost before I had finished, the animal trembled violently, its eyes projected, its breathing became laborious, it fell down and expired. The result could scarcely be attributed to the accidental injection of air into the vein, for the distress began with the injection of the first syringeful, and was only increased by the second; nor is it likely that this accident would happen twice consecutively. I was particularly careful on this point, and the construction of the instrument rendered such an occurrence scarcely possible with ordinary precaution. It is probable that the injection was performed too rapidly, or that the vital powers were lower than usual. In the case of the remaining animal, No. 14, I decided to inject as large a dose as it would bear, stopping the operation at the first sign of trembling, and delivering the liquid very gradually. The first syringeful caused no bad symptoms, and I had just finished injecting the second dose when trembling commenced. It was rather violent for a short time, but soon went off, and in five minutes the animal appeared as well as before. This cow, therefore, bore without inconvenience the injection of 6 ounces of a 4 per cent. solution, containing 105 grains of pure carbolic acid. Careful observations with the thermometer were taken before each operation. There were no more diseased beasts on the farm, or I should have carried my experiments still further. On visiting the farm the next day, I was told that all the animals seemed better; and on testing them with the thermometer that statement was confirmed. I gave directions that each animal was to be drenched with half a wine-glassful (1 ounce) of carbolic acid in a quart of warm water every morning, but in other respects they might be treated as Mr. Tomlinson, a skilful cow-doctor, should direct. Business now calling me to London, I was unable to watch the further progress of these cases. This is to be regretted, as a series of daily thermometric observations would have been of great value in suggesting further experiments. I had, however, frequent accounts sent me. Cow No. 14 continued to improve slowly until convalescent; she is now quite well. Nos. 10, 11, and 12 remained in apparently the same state for four days; they then changed for the worse, and died. It is not improbable that, had I been able to inject a further quantity of carbolic acid during the four days in which they were thus hovering between recovery and relapse, it would have turned the scale, and some of them, at all events, would be now alive and well. The following table gives the thermometric obser If future experiments prove that injection of car. bolic acid or other antiseptic will do good, it is an operation very easily performed. I have injected five animals and taken thermometric observations within an hour. Sulphite or bisulphite of soda apparently occasions some pain, as the animals struggle very much; with carbolic acid I found them tolerably quiet. I have calculated the proportion which the carbolic acid bore to the whole quantity of blood in these operations. Taking the whole amount of blood in the animal at 150 pounds, there were injected into We find in the "Gardeners' Chronicle," No- | considerable time afterwards. A young man, vember 9, 1867, a description given by the of 18 years of age, died in two days from the Hon. W. Hope of experiments made on dis- effects of a tablespoonful of acid. The pathoeased cattle at his farm near Barking. He logical changes are usually limited to the tongue, pharynx, gullet, stomach, and intestines. In most cases these parts are covered by a white coating, which has been described as similar to whitelead. In one case, curiously says: 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 Lancet, June 21, 1873. † Ibid., Feb. 18, 1873. 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. Brandy should be avoided. There is generally great depression of temperature, 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 with nitric or hydrochloric acid and dried, becomes of a bright blue colour. Perchloride of iron added to carbolic acid gives a beautiful mauve or purple colour. A small quantity of the acid put in a testtube, a little saliva added, and then a few drops of tincture of guaiacum, allowed to stand exposed to the air, then shaken, becomes of a bottle-green colour. A weak solution of carbolic acid, to which a little chlorimated lime has been added, and 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, 15203. 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 from time to time on to the substance in a. dilute nitric acid, which is allowed to escape 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 very convenient method of estimating carbonic 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. 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 : |