TREPONEMA PALLIDUM 145 



protected. Against weak bichloride and 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 

 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. 

 No serum of therapeutic value has as yet been produced, nor 

 can immunity be induced by injecting dead spirochetes. A 

 remedy, salvarsan, consisting of a complex arsenical com- 

 pound, has been found to cure syphilis. It is efficacious at all 

 stages, stopping and curing the disease if given at the time 

 of chancre, and materially improving the nervous condition 

 of the late stages. Lately, Noguchi has made an extract of 

 spirochete bodies which can be used as a skin test for syphilis 

 precisely as tuberculin is rubbed into the skin in diagnosis 

 of tuberculosis. He claims good results during the later 

 stages, but as a diagnostic test of recent infection it has not 

 yet proved of value. 



Chancroid. There is a venereal disease known as chancroid 

 or soft chancre in contradistinction to the primary hard 

 chancre of syphilis. This is an acute infectious condition due 

 to the bacillus of Ducrey. The lesion begins as a pustule, 

 which soon breaks down into a spreading ulcer. The disease 

 is communicated by direct contact usually. The bacilli are 

 in the discharges and therefore can be transferred through 

 the intervention of dressings. The bacilli are extremely 

 small, double rods, not motile, and form no spores. They 

 grow on laboratory media containing blood. They do not 

 possess a great viability under artificial conditions, and there- 

 fore are destroyed in discharges quite easily. Simple drying 

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