150 THE MORE CHRONIC INFECTIOUS DISEASES 



carbolic acid it has no resistance. Alcohol will destroy 

 it in five minutes. Up until the beginning of 1911 no 

 success had met attempts to cultivate these spirals 

 in the laboratory. Noguchi finally succeeded in 

 growing them under anaerobic conditions in a mixture 

 of serum and agar to which a piece of sterile liver or 



FIG. 42 



Treponema pallidum appearing as bright refractive body on a dark field, 

 as shown by India ink or ultramicroscope. (Park.) 



kidney of rabbit had been added. Only rabbits and 

 monkeys among the lower animals can be made to 

 contract syphilis, but of these only the latter shows 

 any similarity to man in the course of the disease. 

 When infective crusts from eruptions or serum exuding 

 from them is kept in the test-tube for six hours, 

 infection can no longer be transferred to monkeys. 



