78 . ABSTRACTS.

December and the 13th June the animal received seven injections, for the most part of dried muscle juice. The first of these were given intravenously and the others subcutaneously. In spite of this, it was found that 50 cc. of the cow's serum was insufficient to immunise a sheep. After an interval of several months the cow was again treated with large doses, until it no longer reacted in the least degree and appeared to be perfectly immune. After this I? cc. of the serum sufficed to protect sheep against a fatal dose of the strong VIruS.

THE STERILISATION OF TUBERCULOUS MILK AND MEAT.l

IN a recent contribution on this subject Galtier observes that the numerous investigations which have been made with regard to the action of heat on the tuberculous virus have not all had identical results.

Such virulent matters as sputum, tuberculous lesions, etc., in the moist state, are certainly sterilised by cooking and boiling; and provided the temperature is maintained for a sufficiently long time this effect may be obtained with temperatures as low as 70° C.

In the case of milk, however, an exposure for five or six minutes, even to a temperature of 85° c., may be insufficient to produce complete sterilisation when the material is rich in tubercle bacilli. In support of this statement Galtier gives the following experiments.

1. An emulsion prepared from the spleens and lungs of two tuberculous rabbits recently killed was mixed with a litre of milk. The mixture was then filtered through muslin and divided into four equal parts. One part was employed without heating, and the other three were inoculated after having been heated for six minutes to 70°, 80°, and 90° C. The heating was effected in an open vessel, and the inoculations were made on a series of guinea-pigs by intra-peritoneal injection, the milk being taken from the lower strata by means of a pipette. The four guinea-pigs inoculated with the unheated milk all died between the thirty-eighth and fifty-second day, with the lesions of a generalised tuberculosis. Of the four guinea-pigs inoculated with the milk heated to 70° c., three were found to have some tuberculous lesions when they were killed after fifty-two days, and one of the lot inoculated with the milk heated to 80' C. also presented some tubercles. The four guinea-pigs inoculated with the milk heated to 90° C. were found to be all healthy.

2. This experiment was carried out on the same lines as the preceding one. Infected milk unheated, and heated for six: minutes to 75°, 85°, and.9o ° c.. was inoculated to four series of guinea-pigs, four animals in each series. The results were similar. The four guinee-pigs inoculated with the unheated milk died tuberculous. Of the four inoculated with the milk heated to 75°, three had a discrete tuberculosis, and the fourth was found to be healthy. Of the lot inoculated with milk heated to 85°, two remained healthy and two were found to be tuberculous. The four inoculated with milk heated to 90° all remained healthy.

3. Same manner of procedure. Intra-peritoneal inoculation of infected milk unheated, and heated for six minutes to 75°, 80°, 85°, and 90° c., to five series of guinea-pigs, four animals in each series. Similar results. All the guinea-pigs inoculated with the unheated milk died from tuberculosis. Three of the four inoculated with the milk heated to 75°, two of those in the series inoculated with milk heated to 80° and 85°, and one case in the lot inoculated with the milk heated to 90°, became tuberculous.

1 "Journal de Med. Vet.," .Tanuary 1900.

ABSTRACTS. 79

4. Two young pigs, between two and three months old, were fed on the 4th, 24th, and 28th May, 20th June, and 20th July, 1898, with four litres of milk infected with minced tuberculous lesions. On the first of these occasions about 400 grammes of tuberculous lesions from a cow were added to the milk; on the second occasion, four spleens and four livers from tuberculous rabbits; on the third occasion, three lungs, three livers, and three spleens from tuberculous guinea-pigs; and on the fourth and fifth occasions, two spleens, two livers, and two lungs from tuberculous rabbits. On each occasion the milk thus infected was heated for twenty minutes at 7 S· C. After cooling it was given without filtration to the experimental pigs. One of the pigs was killed on the 7th September, and although then in excellent condition it was found to be tuberculous. The glands of the throat were the parts worst affected, but tubercles were also present in the mesenteric glands, spleen, liver, and lungs. The second pig was killed on the 28th September, and it also, although in good condition, was found to be tuberculous like the first.

Galtier concludes that in order to obviate all risk of infection it is advisable to submit to the boiling temperature the milk of animals suspected of being tuberculous, before allowing it to pass for consumption by human beings or animals.

Galtier also discusses the question whether tuberculous flesh previously sterilised by heat may not be able to produce injurious effects in human beings or animals consuming it, in consequence of toxic substances present in it. Heat does not destroy the tuberculous poison, and it might be suggested that there was some danger through the presence of such poison in the flesh or in the lesions even after cooking.

So far as the flesh of tuberculous animals is concerned there is absolutely no occasion for fear, for proper cooking deprives the flesh of its virulence, and if there is any toxin it must be present in such minute quantity that it may be neglected. As a matter of fact, the muscular tissue is rarely invaded by tuberculous lesions, and experience seems to show that it is not in any degree toxic. Before the institution of a regular inspection of meat almost all tuberculous animals were used for food, and even at the present time a considerable number of them are so consumed. In spite of this, no one has ever brought forward a case of meat-poisoning determined by the consumption of cooked tuberculous flesh. The juice of such flesh and the boullion made from it are not in any appreciable degree toxic.

Finally, the use of sterilised tuberculous flesh for human food which is now practised in several countries has demonstrated that its consumption is quite free from danger.

Everywhere an effort is made to secure the destruction of organs that are manifestly tuberculous, but it frequently happens that parts more or less rich in tuberculous lesions are used after cooking for feeding animals, and it may be presumed that man himself is occasionally exposed to the risk of receiving flesh containing more or less abundantly the lesions of tuberculosis. It is well to know whether there would be any risk of poisoning in such a case, and Galtier has therefore performed the following experiment.

Two healthy young pigs, No. I, weighing 39 kilo., and No.2, 37 kilo., were placed separately, but in identical hygienic conditions and fed alike. NO.2 was not given any tuberculous material, but between the 26th May and the I I th November J899 No. I was fed on ten occasions with tuberculous matter which had been sterilised in the autoclave at 110· C. On the first of these occasions the pig received 500 grammes of tuberculous lesions from a cow; one lung, one liver, one spleen, and one omentum from a tuberculous guinea-pig; and one liver from a tuberculous rabbit. On the second occasion it was given I kilo. of tuberculous lesions from a cow; on the third occasion

80 ABSTRACTS.

2 kilo. of similar lesions; on the fourth, 1500 grammes; on the fifth, 12,000

grammes; on the sixth, 1100 grammes; on the seventh, 1800 grammes; and on the eighth, 2 kilo.-all of tuberculous lesions from cows. On the ninth occasion the pig was given ISO cc. of tuberculin. On the tenth and last occasion it was given 2 kilo. of lesions from a cow. The pig thus fed did not appear to suffer in any way, and it became fat.

GLANDERS. DOES ONE ATTACK CONFER IMMUNITy?l

AMONG the contagious diseases there are some in which a second attack does not occur or occurs only after a long interval. Small-pox and sheep-pox are examples. There are others, such as foot-and-mouth disease, which confer only a partial and not very lasting immunity. Finally, there are some in which a first attack, instead of increasing the resistance of the organism, seems to bring about a greater degree of susceptibility. For example, soft chancre is indefinitely re-inoculable to the same individual, even on the cicatrix ot a previous chancre.

The investigations of Galtier have shown that this is the case with respect to glanders in the dog. Cutaneous inoculation of nasal discharge or glanderous pus provokes in the dog an ulcerating wound, which in the immense majority of cases heals up completely after a relatively short period of time. Recovery from this first attack does not in the least diminish the marked susceptibility of the dog for the virus of glanders. A new cutaneous inoculation is followed by the development of a new sore, just like the first, and, like that, ending in complete recovery. The same dog may thus be repeatedly used for experi­mental inoculations with a view to diagnosis in suspected cases of glanders.

Although it has thus been established that there may be repeated attacks of glanders in the dog when the disease remains localised, this does not apply to cases of recovery from a general infection. As Straus has shown, a dog which resists cutaneous inoculation will succumb when a large dose of the virus is injected into the veins, but if the dose is small the animal may recover after having shown at various points of the body cutaneous ulcers. A dog which has thus recovered from an attack of what may be called general glanders is for the future refractory to the intravenous injection of doses of the virus that are fatal to control animals.

This immunity is not absolute, for it is easily overcome by the injection of small doses of cultures of increased virulence, such as are used in the prepara­tion of mallein; and, strange to say, the dog which is able to resist this intra· venous inoculation may still be inffected by cutaneous inoculation, this being followed by the formation of a glanderous ulcer, exactly as in the case of a healthy dog.

In view of these facts, it is of interest to inquire whether they apply to the horse also, but it has for a long time been impossible to settle the question. It has generally been held that glanders is incurable. It is very well known that the disease may be limited to a small number of lesions situated in the depth of some of the organs, notably of the lungs. But post-mortem examina­tion was formerly the only means of ascertaining whether such lesions were present or not. We are now much better provided with means of diagnosis, even when the only lesions present are a few miliary tubercles scattered through the lung tissue. Mallein reveals their presence with absolute pre-

1 "Recueil de Med. Vet." December 1893.