54 INFECTION AND RESISTANCE 



and guinea pigs can be killed by injections of cultures, but die prob- 

 ably of toxemia. In rabbits a cholera-like condition has been pro- 

 duced by injection of the spirilla into the duodenum after ligation 

 of the common bile duct. (Nikati and Rietsch, Ref. in Deut. med. 

 Woch., Vol. II, 1884, p. 613.) Ordinarily no multiplication takes 

 place in the animal body. Pigeons are insusceptible, a fact which 

 helps to distinguish this organism from Spirillum metcJinikovi and 

 other similar bird-pathogenic spirilla. 



Typhoid fever occurs spontaneously in man only. It has recently 

 been produced in a mild form in chimpanzees. Animals are suscep- 

 tible to the endotoxins and can therefore be killed by injections of 

 bacilli and extracts, but the organism is not invasive as in the case of 

 the lower animals. Typhoid septicemia can be produced in rabbits 

 by inoculating them with especially virulent cultures of the bacilli, 

 or cultures previously grown on rabbit-blood agar (Gay). The ty- 

 phoid-carrier state may ensue for considerable periods in such ani- 

 mals. 



Pneumococcus infection in various forms occurs spontaneously 

 in man. Rabbits, mice, and guinea pigs are highly susceptible. 

 Rats, dogs, cats, cattle, and sheep are relatively resistant. 



Staphylococcus and streptococcus infections may occur in almost 

 all of the warm-blooded animals, chiefly as abscess producers. In 

 horses a severe form of pleuropneumonia is caused by them. 



Leprosy occurs spontaneously in man only. Lesions simulating 

 human leprosy have been produced in monkeys by inoculation, and 

 partially successful experiments have been made upon the Japanese 

 dancing mouse. Other animals are immune. 



Scarlet fever occurs spontaneously in man only. Monkeys may 

 possibly be susceptible, though not all observers have been successful 

 in such experiments. (Draper and Handford, Journ. of Exp. Med., 

 Vol. 17, 1913.) Landsteiner and Levaditi (Ann. Past., Vol. 25, 

 1911) have succeeded in producing the disease in the chimpanzee, 

 though they failed with lower monkeys. 



Small-pox occurs spontaneously in man only. It is probably iden- 

 tical with cow-pox. (See reasons for this assumption given by Ha- 

 cius as cited by Paul in "Kraus and Levaditi Handbueh," etc., Vol. 

 1.) It can be experimentally produced in monkeys. 



Measles develops spontaneously only in man. Macacus rhesus 

 has been successfully inoculated by Anderson and Goldberger (U. S. 

 Pub. Health Reports, 26, 1911). Other animals are immune. 



Typhus fever occurs in man only. Experimentally it has been 

 produced in chimpanzees, Macacus, Cercopilhecus, Ateles, and My- 

 cetes monkeys. Anderson has succeeded in producing temperature 

 reactions in guinea pigs by injecting blood from typhus patients or 

 from other similarly infected guinea pigs. More exact information 

 concerning this disease will probably be available soon, if the re- 



