MEAT AND MEAT PRODUCTS. 9 



body, in which case the poisoning is a true infection. Instances are known where 

 diseases of animals have been transmitted by eating the flesh. 



In view of the fact that bacteria are, above all, the most common cause of poisonous 

 meat, it follows that the examination should primarily be made from that stand- 

 point. To sum up what has already been said: Given a poisonous meat, the first pro- 

 cedure is to detect or exclude the presence of trichinae. If they are not found, the 

 bacteriological examination should next be undertaken, and the chemical examina- 

 tion should be reserved until the last. 



The bacteriological examination should first consist in feeding a number of different 

 species of animals^ the larger the number the better for a day or two exclusively 

 upon the food. White mice, house mice, white rats, young dogs, cats, rabbits, or 

 guinea pigs can be used. If the animals sicken and die they are to be subsequently 

 examined for the presence of pathogenic bacteria. It may happen that none of the 

 animals thus fed will be injured by the food, which fact would not exclude, how- 

 ever, the presence of a germ requiring a specially susceptible animal for a subject. 



Another set of animals should be injected with a cold extract of the meat made 

 with sterile water. If the animals die, they are to be examined for pathogenic bac- 

 teria. A third set of animals should receive similar injections, though of larger por- 

 tions, of this aqueous extract which has been previously filtered through sterile 

 porcelain. If the animals die from such injections the same as with unfiltered solu- 

 tions, it is evident that a soluble bacterial chemical poison is present. 



The identification of the toxin or real poison produced by the germ is wholly out 

 of the question. The most that can be done satisfactorily is to obtain,* as above, a 

 germ-free solution of the poison. It is wholly unnecessary to devote any space in 

 this connection to the detection of the basic bacterial products, the ptomains, since 

 these bodies are mere cleavage products produced by some and not by other bacteria. 

 Moreover, they are usually but very feebly poisonous, and for that reason they do not 

 hold the prominent position formerly ascribed to them a . 



A bacteriological examination proper should be made of the original poisonous 

 meat and of all the animals that died cither from outing the meat or from the injec- 

 tions of the aqueous extracts. The organism present in the animal, if any, must be 

 isolable directly from the meat. If it happens, as it sometimes has, that the dead 

 animals contain no germs, it is proof that they were killed by u toxin elaborated by a 

 germ in the meat previous to the injection. Cultures from the meat will then reveal 

 the germ, and the effects of its pure cultures should correspond to those observed 

 with the poisonous meat. 



To prepare the cultures from the original food, the latter should be cut out with a 

 sterile knife and material should be taken from the inside, thus avoiding all chances 

 of contamination. Several sets of beef-tea tubes and agar plates should be made. 

 One set should be set aside in a Novy anaerobic jar at room temperature; a second 

 similar set should be placed at a temperature of 37 C. A third set should be grown 

 in the presence of air at room temperature, and a like set at a temperature of 37. 



The full details of bacteriological methods must obviously be omitted in this con- 

 nection. Such work requires a special laboratory and special drill. Those who may 

 be further interested are referred to the works of Abbott, Novy, and Sternberg. 



3. PREPARATION OF SAMPLE FOR CHEMICAL EXAMINATION. 



In the case of fresh meat, separate the sample as completely as possible from the 

 bones and pass it rapidly and repeatedly through a sausage mill until thorough 

 mixture and complete maceration are obtained. The sample must be kept on ice to 

 prevent decomposition, and all of the determinations should be begun as soon as 

 practicable after the sample is prepared. In the case of canned meats, pass the 



For detailed methods see Vaughan and Novy, "Cellular Toxins," 4th edition, 1902. 



