The Cardinal Conditions of Infection 81 



correctness is not wanting. Charrin and Roger* found that 

 white rats, which naturally resist infection with anthrax, 

 succumbed to the infection if compelled to turn a revolving 

 wheel until exhausted before inoculation. 



(c) Exposure to cold seriously influences the resisting 

 power of the warm-blooded animals. It is an everyday 

 experience that chilling the body predisposes to "cold" and 

 may be the starting-point of pneumonia. Pasteur found 

 that fowls, which resist anthrax under normal conditions, 

 succumbed to infection if kept for some time in a cold bath 

 before inoculation. 



The reverse seems to be true of the cold-blooded animals, 

 for Gibierf found that frogs, naturally resistant to the 

 anthrax bacillus, would succumb to infection if kept at 37 C. 

 after inoculation. 



(d) Diet produces some variation in the resisting powers. 

 The tendency of scorbutics to suffer from infectious dis- 

 orders of the mouth, the frequency with which epidemics 

 of infectious disease follow famines, and the enterocolitis of 

 marasmatic infants, illustrate the effects of insufficient food 

 in predisposing to disease. We also find that the infectious 

 diseases of carnivorous animals are not the same as those of 

 herbivorous animals, and that the former are exempt from 

 many disorders to which the latter quickly succumb. 

 Hankin was able to show experimentally that meat-fed rats 

 resisted anthrax infection far better than rats fed upon 

 bread. 



(e) Intoxication of all kinds predisposes to infection. 

 PlataniaJ found that such animals as frogs, pigeons, and 

 dogs became susceptible to anthrax when under the influence 

 of curare, chloral, and alcohol. Leo found that white rats 

 fed upon phloridzin became susceptible to anthrax. Wag- 

 ner || found that pigeons become susceptible to anthrax when 

 under the influence of chloral. Abbott** found the resisting 

 powers of rabbits against Streptococcus pyogenes and 



* " Compte rendu Soc. de Biol de Paris," Jan. 24, 1890. 

 t " Compte rendu Acad. des Sciences de Paris," 1882. t. xcix. p. 

 1605. 



t See Sternberg's " Immunity and Serum Therapy," p. 10; " Cen- 

 tralbl. f. Bakt.," etc., Bd. vn, p. 405. 



" Zeitschrift fur Hyg.," Bd. vn, p. 505, 1889. 

 || " Wratsch," 1890, 39, 40. 

 **"Jour. of Exp. Med.," vol. i, No. 3, 1896. 

 6 



