EMPHYSEMATOUS ANTHRAX.
Definition. Historic notes. Geographical distribution. Animals susceptible: Young cattle after weaning, sheep, goats; horses, asses and white rats, have local swelling; dog, cat, pig, bird and man immune. Immune animals succumb if injected with lactic acid, or proteus vulgaris, or violently exerted (sarco-lactic acid). Causes. Bacillus anthracis emphysematosa, 3 to 10μ by 5μ, stains violet with iodine, anærobic, sporulates in living body, hence seen as rod, club, and round, spore. Lives in exudate, not in blood nor on surface. Table comparing with anthrax bacillus. Vitality: resists drying, cold, 98° F., weakened by 139°, sterilized by 212° F. for 20 minutes, by strong antiseptics. Lives in dense clay, hard pan, and waterlogged soils holding little oxygen. Accessory causes: lactic and other organic acids, overwork, potash salts, alcohol, salt, proteus vulgaris, micrococcus prodigiosa, low condition, debility, plethora, chills, change to warmth, youth, melting snows, freshets, drying of wet lands. Symptoms: incubation a few hours, disease 12 to 70 hours. Hyperthermia, swelling in loose connective tissue, shoulder, quarter, arm, thigh, neck, trunk, palate, base of tongue, pharynx, tender point, rapidly enlarges, spreads, crepitates, percussion resonance, finally cold, insensible, and withered. On incision black, bloody pulp, or frothy. Peripheral gelatinoid exudate. Subsidiary lymph glands enlarged. Cases with deep seated exudate. Diagnosis: from malignant œdema and anthrax. Lesions: early decomposition, bloating, in swelling blood extravasation with gas bubbles and lymph exudate, muscle beneath dirty brown or black, breaking down when pressed, shows waxy or fatty degeneration, and many leucocytes and cell forms. Lymph glands and plexuses blood gorged. Extravasation may be in internal organs. Liver congested. Spleen rarely enlarged. Treatment: Chloride of iron internally, ammonia iodide and ol. terebinth externally. Scarify and use hydrogen peroxide or potassium permanganate. Antitoxins. Prevention: drain and till soil, apply quicklime to muck, exclude new animals just from infected districts, disinfect buildings, close infected wells and streams, seclude the sick, burn, cook or dissolve carcasses, or fence graves. Bleeding purgation, diuresis, uniform good feeding, setoning. Immunization by heated and sterilized culture; by toxins passed through a porcelain filter; by minimum dose intravenously; by injection into trachea; by inoculation on tip of tail; by inoculation with Pasteur weakened virus; by heat sterilized virus.
Synonyms. Symptomatic Anthrax; Black Quarter; Quarter Ill; Black Leg; Rauschbrand; Charbon Symptomatique.
Definition. An acute infectious bacteridian disease manifested by hyperthermia, lameness, and a localized, hot, painful swelling on the shoulder, quarter, leg, neck, trunk or elsewhere, tending to emphysema, and gangrene and when incised showing black extravasated blood, clotted or frothy.
This affection was long confounded with anthrax proper, but was differentiated by the observation of Wallraff (1856), Boulit-Josse, Vernant, Pfisterer, Feser, and others and finally Bollinger in 1875 found the motile bacillus. Arloing, Cornevin and Thomas (1879–84) thoroughly substantiated this position, and devised a method of immunizing by inoculation. Feser had however seen the motile sinuous rods in the exudate as early as 1860, and even produced the disease by the inoculation with mud from infected Alpine pastures.
Geographical distribution. Emphysematous anthrax prevails in limited areas, and particular buildings in Europe, Asia, Africa, Australia and America, and in all climates from the tropics up to the sub-Arctic. It is however most prevalent in spring, summer and autumn. It is not uncommon at the breaking up of the winter snows. It is especially prevalent on damp, undrained land or on such as has dried up in the heats of summer, and has become less prevalent in many localities in connection with drainage and careful cultivation.
Animals susceptible. The disease is especially common in young cattle, from three months to four years of age. Calves fed on milk are rarely attacked, being in a sense carnivorous and sometimes immunized by toxins from the dam. Cattle over four years usually escape, having already become immune if kept in an infected locality. If brought from a noninfected place they are, at any age, as susceptible as the young. Sheep and goats contract the disease only exceptionally, but like the Guinea pig are easily infected by inoculation. Horses, asses and white rats have only a circumscribed swelling in the seat of inoculation, and foals and buffalo calves sometimes contract it casually. Carnivora and omnivora, (dog, cat, pig, bird, man), and the rabbit are virtually immune.
Immune animals may, however, be made to succumb under special treatment. In a rabbit inoculated at the same time with the microbe of black quarter and proteus vulgaris, or micrococcus prodigiosus, or if injected with a little lactic acid, the disease develops promptly and fatally. Over-exertion, producing sarco-lactic acid will also lay the system open to attack. The reduction of the vitality and resistance of the muscle of the rabbit by a contusion, bruise or lacerated wound, or by injecting it with acetic acid, potash salts, alcohol, or common salt, will render the inoculation pathogenic. Again, the introduction of the black quarter microbe into the aqueous humor of the rabbit, where there are so few defensive leucocytes, entails an active proliferation and a fatal result.
Causes. The essential cause of emphysematous anthrax is a rod-shaped germ, variously known as bacillus anthracis emphysematosa, bacillus Chauvæi, Rauschbrand bacillus. This is a rod-shaped microbe, with rounded ends, found singly or connected in pairs, or very short filaments. The bacilli are 3 to 10µ long, by .5µ broad, or when sporulating, 1.1 to 1.3µ. They form spores even in the body of the affected animal, often assuming a club shape by reason of the spore formation near one end. If the spore develops in the center they appear fusiform. They take aniline colors readily, and iodine slightly, assuming in the last case a violet tint. The staining is unaffected by heating in melted balsam. The bacillus grows readily in ordinary culture media, (peptonized gelatine, bouillon, milk, etc.), but, being anærobic, only under the surface in stick cultures, or under a neutral gas or vacuum. It grows most rapidly at a temperature of 36° to 37° C. but also as low as 15° C. The bouillon at 37° C. becomes milky and opaque in 24 hours, and later it clears up, the microbes being precipitated as a free white powder. In gelatine cultures liquefaction takes place in three days, and in twenty days the whole mass may be dissolved and the microbes precipitated to the bottom. Spores may form in the living body and as these are set free by the granular degeneration of the bacilli, the virulent exudate and cultures usually show the microbe in three different forms: 1st; the straight, motile bacillus of one thickness throughout its whole length; 2d; club-shaped or fusiform bacilli, the thickening of the end or median part being due to the endogenous formation of a refrangent spore or spores; and 3d; the free refrangent spores which have been set free by the degeneration and destruction of the sporulating bacilli. The microbe is not found on the surface of the living animal, nor in the blood, for in both the supply of oxygen is too abundant; it forms its colony under the skin, in the tissues, and above all, in the mass of extravasated blood or gelatinoid exudate which its irritation has produced and where air is lacking.
The most marked differential features of the microbes of anthrax and emphysematous anthrax are contrasted in the following table:—
| Bacillus Anthracis. | Bacillus of Emphysematous Anthrax. |
|---|---|
| 5 to 20μ × 1.25μ. | 3 to 10μ × 0.5 to 0.6μ. |
| Ends square or cupshaped. | Ends rounded. |
| Occurs singly in the living body. | Often in pairs or threes in body. |
| Long filaments in cultures. | No long filaments. |
| Nonmotile. | Motile (sluggishly). |
| Ærobic. | Anærobic. |
| No spores formed in living body. | Sporulates in living body. |
| Sporulates in air; in surface soil. | Sporulates in vacuo; deep in soil. |
| Bacilli only. | Bacilli; sporulating bacilli; free spores. |
| Multiplies freely in blood stream. | Dies in blood stream unless charged with toxins. |
| Rabbit very susceptible; man less so. | Rabbit, pigeon and man immune. |
| Produces no gas. | Gas producing. |
| Inoculation swelling very restricted. | Inoculation swelling very extensive. |
| Bacillus destroyed by putrefaction. | Not destroyed by putrefaction. |
Resistance of bacillus of black quarter to physical and chemical agents. The microbe is possessed of great vitality. Thoroughly dried at a temperature of 95° F. it retains its virulence. The spores may be preserved indefinitely in dry soil, buildings, fodder, litter, harness, etc. Cold is equally harmless to it. It has been exposed to a temperature of 98° F. below zero without losing its virulence. Its virulence is lessened by exposure for an hour to 139° F., and it is sterilized at a temperature of 212° F. for twenty minutes. The dried spores are virulent after six hours of the boiling temperature but are sterilized at 230° F. if maintained for the same length of time. Diffused in water the virus is sterilized in thirty-five minutes at the boiling temperature. Some waters at ordinary temperatures destroy the virulence in twenty-four hours; others not for many months. It is destroyed by the more potent disinfectants, mercuric chloride (1:1000), silver nitrate (1:100), acid salicylic (1 to 2:100), acid carbolic (2 to 4:100), copper sulphate (20:100), boric acid (20:100), muriatic acid (1:2). Quicklime, copperas, zinc chloride, sulphuric acid and an alcoholic solution of phenol have proved unsatisfactory.
In clay soils, hard pans, waterlogged soils, and in some that are over manured so that the atmospheric air is excluded, it may be preserved indefinitely. Feser, Gotti and others have produced the disease by inoculating with the washings of infected marshy soils, and this is doubtless a common source of casual cases of the malady.
Accessory causes are important. The predisposing influence of lactic acid, of other organic acids, and of overwork have been already named. Potass salts, alcohol, common salt and the products of proteus vulgaris, or micrococcus prodigiosus increase the susceptibility. Low condition, debility, or suddenly induced plethora have a similar influence. Sudden changes of weather, chills, and particularly the access of hot weather in spring, when the animal is changing its coat lays, the system open to attack. Youth, after the period of suckling, and under three years old, seems to increase the predisposition, though this is largely the result of the absence of a previous exposure. Then impermeable, clay, wet, marshy soils, or those charged with organic matter are conditions of the presence of the microbe. It often appears in spring in connection with the melting of the winter’s snows, the occurrence of freshets, and the washing out of soil infection which would otherwise remain buried. Also in advanced summer and autumn when swamps, ponds, basins, deltas, river bottoms, etc., are drying out and furnishing pasture. Pease records its great prevalence in the rainy season in the swamp districts of the Punjab and North Western provinces of India, and the same is largely true of our Gulf coast states.
Symptoms. Emphysematous anthrax develops suddenly, the incubation in experimental cases, lasting only for a few hours, and the whole course of the disease does not usually exceed ½ to 3 days. The local swelling may be the first observed symptom or there may be first febrile disturbance followed by the local swelling. The swellings show where the connective tissue is loose and abundant as on the shoulder, quarter, arm, thigh, neck, face, or trunk, and practically never where the areolar tissue is very spare and dense as on the end of the tail, or ear, or on the limb below knee or hock. They sometimes form on the palate, base of the tongue, or pharynx. The muscular system is especially liable to suffer, the looseness of the texture and the presence of lactic acid making a particularly favorable field for the propagation of the microbe. The comparative absence of muscle in the region below the metacarpus, the tail and ear is an important cause of this immunity.
The swelling is at first very small and tender, but it encreases rapidly, and in a few hours may extend to one, two, or three feet in diameter. At first smooth, rounded, pitting on pressure and destitute of crepitation on handling, it becomes softer and less sensitive and when pressed or kneaded it gives a crepitant sensation and sound, or it even appears to gurgle. When percussed the resonance is drumlike. Finally, the skin may become cold, insensible, and withered like a piece of parchment. When incised the tissues are found to be gorged with blood, and of a black or dark red color; they break down under pressure into a bloody pulp, and from the wound flows a bloody fluid which may be red in the early stages, black in the advanced, and frothy in the latest. Where the connective tissue is very loose and abundant, the bloody extravasation is surrounded by an extensive straw colored œdematous infiltration. The swelling is sometimes single, but more frequently several appear and become confluent. The lymph glands in the vicinity become greatly enlarged.
Fever is a constant condition as the swelling advances and sometimes it precedes the local engorgement. There is erection of the hair, with it may be, distinct shivering, recurring again and again. Then general stiffness, dulness, prostration, loss of appetite and rumination, accelerated breathing sometimes attended by a grunt or moan, and rapid pulse. The temperature usually reaches 104° F., and may rise to 109° F. The breathing becomes more and more labored and plaintive, colicy symptoms may set in, the prostration advances to complete adynamia, the patient can no longer stand, the temperature drops to 100° F., or 98° F., and death supervenes in from eight hours to two days from the first sign of illness.
In some cases the swelling may be invisible because it is situated deeply or it may perhaps be entirely absent, and the constitutional symptoms are the only ones observed.
Diagnosis. From malignant œdema, which it resembles in producing gas and crepitating tumors, emphysematous anthrax is distinguished by the greater length of the microbe, by its formation of spores at the pole and not in the centre of the bacillus, by the more sluggish motions of the germ, by the restriction of the germ to given infected districts instead of being generally diffused as in malignant œdema, by its not attacking man, rabbit, nor pigeon, which are subject to malignant œdema, by its deadly action on mature cattle which are usually immune from malignant œdema, and by the abundant blood extravasation on the swelling.
From anthrax it is distinguished by the motility of the bacillus, by its polar sporulation and club shape, by its rounded ends, by its absence from the blood in the earlier stages, by the presence of gas and crepitation in the swellings, and by the deadly action of the infection on Guinea pigs, but not on rabbit, man, nor pigeon. Anthrax is easily inoculable on a cutaneous sore or intravenously whereas emphysematous anthrax is not.
Lesions. The carcass is liable to be bloated with gas and a reddish, frothy liquid often escapes from mouth nose and anus. Gas is particularly abundant in the substance of the tumor, and the skin covering it may be dry and crackling. An incision made into the swelling exposes a mass of blood extravasation and lymph exudate, the blood predominating in the centre so that it may appear clotted and black, and mixed with gas bubbles, while the yellowish lymph forms the periphery of the tumor, yet streaked more or less with blood, or even pink throughout. The abundance of gas is usually in inverse ratio to the amount of œdema. The muscles beneath or surrounded by an exudate are of a dirty brown or black, and are disintegrated so as to break down readily under pressure of the finger into a blackish pulp. They are infiltrated with gas, crepitate under pressure and assume a golden yellow color on exposure to the air. The gas is comparatively inodorous immediately after death, being mainly carbon dioxide and carbide of hydrogen. Later it may show distinct and even offensive odor, from the formation of hydrogen sulphide, or lactic acid. The muscular fibres are easily teased apart, and show under the microscope masses of blood globules, leucocytes, lymph cells, free nuclei and granules, with, in some points, fatty or waxy degeneration of the fibres, or granular masses that are stained black by osmic acid. The bacillus is present in large numbers, and this with its absence immediately after death from the blood becomes characteristic. The lymph glands near the swelling are usually enlarged and gorged with blood. The lymph plexuses and vessels contain bubbles of gas.
The swellings may be subcutaneous, or submucous in the tongue or pharynx, but they occur also in the pleuræ, lungs, heart, pericardium, mediastinum, the peritoneum, the sublumbar connective tissue, and even the walls of the stomach or intestine. It is not uncommon to find a pink effusion into one of the serous membranes. The liver is usually hyperæmic, as may be also the kidneys, but the spleen is rarely enlarged. In this and in the integrity of the blood globules this affection differs from anthrax.
Treatment. This disease is so often speedily fatal, cutting off its victim in eight hours, often during the night, that no opportunity is allowed for treatment. Even in those that survive for two days, the affection must always be looked on as exceedingly grave, and as little amenable to treatment. Yet much depends upon the patient and the country. Dr. Phares in Mississippi found that it yielded readily in many cases to ½ oz. doses of tincture of chloride of iron every four hours, and a local application composed of equal parts of tincture of iodine, aqua ammonia and oil of turpentine. Galtier tells us that recoveries are frequent in Algeria, while they are rare in France. Tisserant gives the French recoveries as 2 per cent. It is probable that in districts and countries where the malady is all but ubiquitous, the surviving animals are racially immune, or they have been largely exposed and in some degree virtually immunized at an early age.
Wallraff mentions a success from applying a tight ligature around an infected limb, above the seat of the tumor and freely scarifying the latter so as to freely admit the air. For swellings elsewhere, scarifications and the free application and injection of peroxide of hydrogen or potassium permanganate (2 to 3:100) would be rational treatment. The same agent might be given by the mouth in doses of 2 or 3 ozs. at frequent intervals. Antiseptics and tonics have been freely employed, including phenol, salicylic acid, sodium salicylate, potassium iodide, quinia, alcohol, phosphorated oil, ammonia acetate, and as an eliminant soda sulphate, but with no very good result. Locally, scarification, antiseptics and caustics, have been employed.
Another line of treatment which deserves to be further exploited is the use of antitoxins on infected animals. An immunized animal may be again and again inoculated at intervals of a week or two until it has been stimulated to produce antitoxin in large amount. Then after three weeks interval its blood serum or blood, may be sterilized by heat, the resulting coagulum washed in distilled or boiled water, and filtered, and the filtrate injected subcutem on the infected animal.
Prevention. This is most effectively secured by sanitation of the soil and buildings. Thorough drainage to secure perfect and constant æration leads to destruction of the anærobic germ, or the suspension of its pathogenic quality. Thorough culture contributes largely to this sanitary æration, while baking of the surface counteracts it. When thorough drainage is impossible it may be desirable to subject the land to gardening or to the production of crops that are to be used for human consumption and not for domestic animals. Kitt’s suggestion, to soil cattle on hay, produced on such lands, and to exclude from the infected lands all animals that by wounds or sores near the feet, or by raw gums from shedding of teeth, furnish infection atria for the poison, is insufficient, as stalled cattle occasionally suffer.
When an open porous soil maintains the infection by reason of the presence of an excess of decomposing organic matter, that may be largely remedied by a free application of quick lime. This hastens the decomposition of the organic matter and after a year or two, when that has been largely disposed of, the good effects may be expected.
An important measure is to exclude from fairs, markets, and above all from clay or other dense wet soils into which they might convey the germs, all animals brought from infected soils.
Disinfection of the buildings where diseased and infected animals have been is an essential measure. Wells and streams receiving the drainage of infected lands must be carefully avoided.
Diseased animals must be carefully isolated, and all their droppings, and products of every kind disinfected.
The carcasses are best cremated or rendered under superheated steam under pressure. Solution in sulphuric acid may be employed. If none of these are available they may be deeply buried in dry porous soil well apart from any risk of drainage into wells or water supplies. The area occupied by the graves should be fenced in so that no cattle nor sheep can gain access to it, and any vegetation grown on the graves should be burned. The danger of the germs being raised to the surface by soil water or earth worms must be recognized and any consequent evil guarded against. The carcass should not be cut open but buried in the hide, or if the latter is preserved it should be treated with a chloride of lime solution. If a carcass is opened for scientific purposes, great care must be taken to avoid the distribution of the bacillus in soil appropriate to its preservation. The meat should not be preserved for human consumption unless it has been cooked under pressure at a temperature of 240° F. The object is not to destroy any poison which would be fatal to man, but rather to prevent the spread of the spores on new soil and the extension of the area of infection.
The reduction or prevention of sudden plethora was formerly availed of to lessen the number of victims and it is well to still bear in mind that this has an appreciable though limited effect. As a means of reducing plethora a free bleeding was resorted to when the period of yearly prevalence approached, and no less when the disease had already appeared in a herd. I can mention an instance in which infection was carried on the fleam from the first animal bled (the sick one) and caused the fatal infected swelling around the phlebotomy wound in the next seven animals operated on. Another objection to phlebotomy is the tendency to a rapid reproduction of blood, which the depletion brings about, and the supervention of a greater danger than before, in the course of a month or more. Purgatives and diuretics are somewhat less objectionable in this sense. Careful feeding to keep the animal constantly in good condition does something to obviate sudden plethora and its attendant dangers, and thus an allowance of grain or linseed cake through winter and early spring, or when the pastures are bare, will bring the animals through in fine condition, and ward off the danger that comes from a sudden access of rich aliment.
Another measure was the insertion of a seton in the dewlap. The theory was to counteract plethora but the benefit probably came rather from the formation of an actively granulating wound, which came in contact with the ground and received the bacillus, but in which the abundance of air, and of active leucocytes checked the propagation of the germ and the occurrence of a fatal infection. A certain grade of immunity was the natural result in many cases.
Immunization. As the first attack of emphysematous anthrax secures for the subject of it immunity against a second, we are furnished with a reasonable basis for the practice of artificial immunization. This has been attained by a variety of methods, the essential feature of each being the subjecting of the system of the animal to be treated, to the action of the toxins of the specific bacillus.
1st. A culture of the bacillus made in the thermostat at 42 C. (107.6° F.) so as to prevent the formation of spores is then sterilized by heating to 100° C. for one hour and then injected subcutem in a dose of 2 drams, to be repeated on the second day. This, like all the other methods named should be done by some one accustomed to bacteriological manipulation and the sterilization completed by superheating the neck of the vessel containing the mixture. Any germs escaping on the hands, instruments or other objects used will prove fatal in spite of all the appearance of precautions.
2d. Roux sterilized his cultures by filtering them through a porcelain (Pasteur) filter and using only the filtrate for injection. This requires even greater precaution in manipulation as what is left in the filter is most virulent, and must be thoroughly sterilized to obviate dangers from its dissemination.
3d. Intravenous injection of a small quantity of virus, containing but a few bacilli produces no local swelling, but only a slight temporary hyperthermia and permanent immunity. The greatest care is necessary in the manipulation, to prevent any contact of the bacillus with the subcutaneous tissues or the walls of the vein. The virulent exudate swarming with bacilli is taken and a drop or two added to a normal salt solution, which is diluted and shaken in a stoppered bottle, until each drop contains but one, or at most two bacilli. Then the hands having been thoroughly washed with soap and warm water and rinsed in a 5 per cent. solution of carbolic acid, and the instruments having been boiled, the vein is raised as for bleeding, and penetrated by a short cannula and trochar, which after boiling has been dipped in the carbolic acid solution, the trochar is withdrawn, and the nozzle of the syringe containing the virulent solution is inserted through the cannula, so that its point is free in the centre of the blood stream, into which a few drops of the virulent solution are discharged. The nozzle is left in place for a few seconds to ensure the washing of any infecting matter from its point, when it is withdrawn, followed immediately after by the cannula. Great care should be taken to avoid any scratching of the inner coat of the vein with the cannula, trochar or nozzle.
4th. Another method of immunizing is by the injection of the virulent liquid into the trachea and bronchia. This appears to bring it so directly in contact with the blood, that the microbes are destroyed as rapidly as if it were introduced into the blood stream direct. The injection is made between two tracheal rings, the manipulation being essentially the same as in the cases of the vein, the tissues being first perforated by a sterilized cannula and trochar, and the sterilized nozzle subsequently inserted through the cannula.
5th. Inoculation into the tip of the tail can be successfully employed, the coldness of the region and the scantiness of the connective tissue preventing any dangerous increase of the bacilli in the cooler season. In the heat of summer, however, this is to be avoided as dangerous. The tail is first washed with soap and water followed by a 3 per cent. solution of phenol. It is then punctured with a fine trochar or needle, (sterilized), within two inches of the tip and in a downward direction and the instrument is moved slightly from side to side so as to form a small sac, and is then withdrawn. The sterilized nozzle of the hypodermic syringe is now inserted in the opening and a few drops of the virus injected into the sac. When the nozzle has been withdrawn the thumb may be placed on the external orifice and the end of the tail manipulated to diffuse the virus in the connective tissue. This is usually followed by an insignificant swelling, and a slight rise of temperature. Should the swelling exceed the size of a duck’s egg or if others appear higher up on the tail, they may be freely scarified and covered with a carbolic acid bandage. Or the tail may be amputated above the highest swelling and the stump treated with antiseptics.
6th. The virus prepared by the Pasteur institutes, that of Arloing, Cornevin and Thomas, is the most extensively employed. Forty grammes of the diseased muscle are dried rapidly at 32° C (90° F.) and triturated in 80 grammes of water. This is divided in 12 equal parts and put on plates in two thermostats, six at 100° C. (212° F.) and six at 85° C. (185° F.) where they are kept for six hours, when it forms a dry, brownish powder. One tenth of a gramme (1½ gr.) of this powder is dissolved in five grammes of distilled or boiled water and will furnish ten doses. The animal to be protected is first injected in the tip of the tail or elsewhere with the virus prepared at 100° C., and ten days later with that prepared at 85° C.
By the use of this method in hundreds of thousands of animals on infected lands the mortality has been reduced to less than one tenth of its former amount. It is attended by the one danger which is not always duly appreciated, that unless its use is restricted to herds on ground that is already infected, it endangers the infection of new districts. The spores are not absolutely sterilized at 85° C. Arloing and Cornevin and later, Nocard and Roux have shown that the addition of lactic acid to the liquid which has been weakened for inoculation, restores it to its former virulence, making it a most deadly agent. Galtier says that the virus weakened by heating to 100° C. for seven hours until it will no longer kill a mature Guinea pig, will still kill a new born Guinea pig and acquire all its original virulence in the act. Also that the injection of large enough doses will not only kill the full grown Guinea pig, but at the same time restore the microbes to their former virulence. While recognizing the great economy of the judicious use of such weakened virus, we cannot but condemn the reckless sale by the Pasteur institutes of their products, to be used on animals on all kinds of lands, the uninfected as well as the infected. A great and valuable prophylactic measure should not be used in such a way as to increase the area of prevalence of the disease which is to be prevented, and also the yearly demands for more of the preventive agent. This may appeal to the business instinct, but this should ever be held subordinate to sanitary considerations. The danger might be avoided by making the state the sole distributor of such prophylactic agents, but in any case their use should be forbidden, and as far as possible prevented, upon dense and wet soils that are not yet contaminated by the bacillus.
7th. Kitt secured immunization by inoculating once only, with dried virus which had been subjected for six hours to steam at 100° C.
8th. In different outbreaks, I have taken the blood from the sick animal, or one that has just died, and heated it for over one hour in a water bath, at 100° C., then broken up the coagulated mass in well boiled water, filtered the liquid and used the filtrate for inoculation in doses of 2 drams, repeated the second day. Great care is taken in keeping the whole mass at 100° C. for the requisite length of time; then in heating the upper part of the vessel, which was above the contents and the water so as to char anything adhering to it; to see that hands, instruments, and all articles used have been thoroughly sterilized; and to dip the hypodermic nozzle in carbolic acid before each injection.
It is not claimed that this method is perfect, since severe, advanced cases may have bacilli and even spores in the blood, and the latter would not be sterilized but only weakened. It has, however, several manifest advantages that may be held to more than counterbalance this danger.
a. It almost infallibly secures the toxins of the disease prevailing in the particular herd, thus escaping the danger of using the weakened virus of emphysematous anthrax on some other disease (anthrax, Wildeseuche, Barbone, etc.), which has been mistaken for it, and which may not be prevented by this purchased product.
b. During life the blood of emphysematous anthrax is usually free from the microbe, and even where that is present it is liable to be in very small numbers, so that we secure either the pure toxins, or if a few germs are present they are so scanty, that weakened as they are by heat, they are without danger to the animal operated on. I have never had occasion to note evil results.
c. There is no danger of the spread of the bacillus to new territory, as we secure the material from a herd in the already infected territory, and use it only on the animals on the same land.
The certainty of results with this method, and the comparative absence of danger of injury to the animal operated on, and of all risk of the extension of the area of infection appeal to me so strongly, that I would not willingly resort to the purchased products, except where it proves impossible to secure the virus on the spot.