554 MICRO-ORGANISMS AND DISEASE [chap. 



frog or a normal adult white rat is insusceptible to anthrax 

 infection, but if it be subjected to narcosis with ether- 

 chloroform it becomes susceptible (Klein and Coxwell). 

 Fowls are insusceptible to anthrax, but if cooled they 

 become susceptible (Pasteur). 



Charrin and Roger {La Semaine Med., 1890, No. 4) 

 show that while normal rats are, as is known, very little 

 susceptible to anthrax, they become highly susceptible if by 

 working at a treadmill they are made fatigued, and H. Leo 

 (Zeitschrift f. Hygiene, vii. 3) finds that by the presence of 

 much sugar in the blood and tissues the susceptibility to 

 anthrax and tubercle is not increased, while for glanders it 

 becomes greatly enhanced. Phloridzin is administered in 

 small doses with the food, sugar thereby becoming present 

 in the tissues. Rats thus prepared resist anthrax as much 

 as unprepared rats, guinea-pigs first prepared with phloridzin 

 and then inoculated with tubercle do -not show more 

 intensive or more rapid tuberculosis. While normal white 

 mice are almost insusceptible to glanders, they become 

 highly susceptible to such infection if prepared with 

 phloridzin. Maya and Sanarelli give an account (Fortschr. 

 d. Med., ix. No. 22) of a large number of experiments, in 

 which by introducing acetylphenylhydrazin into an animal 

 insusceptible to a particular disease this animal becomes 

 thereby susceptible. This substance is known to produce 

 destruction of the red blood-corpuscles (Gottstein) and 

 hsemoglobinsemia ; pigeons and rats thus prepared proved 

 susceptible to anthrax. 



{c) A normal guinea-pig when injected subcutaneously 

 with a moderate dose of cholera vibrio not of high virulence 

 from the outset, or that had owing to subculture for many 

 generations lost its virulence, fails to show any result, but 

 when the dose is transmitted through the peritoneal cavity of 



