314 MICRO-ORGANISMS AND DISEASE [chap. 



are quiet, refuse food, the temperature is raised, and at the 

 seat of inoculation is a painful swelling ; some animals die 

 after two, three, or four days, others Hve to the end of the 

 week. On post-mortem examination the same appearances 

 of the viscera, notably of the lungs and kidney, are found ; 

 and here also the fatty white kidney and the pneumonia are 

 the more marked the longer the duration of the disease ; in 

 animals that die forty-eight to seventy-two hours after inocu- 

 lation with culture the subcutaneous and muscular tissues 

 about the seat of inoculation show much hemorrhage, in 

 many parts the tissues are almost gangrenous. On the 

 death of the animal, the bacillus diphtheriee can be re- 

 covered by cultivation in numerous colonies, but no bacilli 

 can be demonstrated in the lungs, liver, or kidney. 



The dog is similarly affected by subcutaneous injection of 

 virulent diphtheria culture. 



Different animals offer, however, different degrees of 

 resistance to infection with living culture or with toxin 

 produced by Roux and Yersin's method in broth culture and 

 separated by filtration with a Chamberland filter. Thus 

 the sheep and goat, the ass and the horse, offer different 

 degrees O'f susceptibility ; the sheep and goat react well 

 (Behring), the ass better, and the horse as a rule least 

 (Roux) ; in the latter animal the relative dose of living 

 culture or toxin can be taken greater than in the ass in 

 order to produce a positive result, but also amongst horses 

 the resistance varies in different animals. On subcutaneous 

 injection of a non-fatal dose a tumour is formed at the 

 seat of inoculation, the body temperature is raised next day 

 (by 0-5-2° C. according to the dose and virulence of the 

 material), the animals are quiet and do not feed quite in the 

 normal manner. But they soon again recover their normal 

 temperature, feed again well, the local tumour becomes 



