260 



BACTERIOLOGY FOR NURSES 



FIG. 37. Treponema Pallidum. 



bending of the entire body. It is thought by some observers that 

 division takes place in a longitudinal rather than a transverse direc- 

 tion, as among many of the protozoa. The organisms are seen with 

 difficulty in unstained preparations by ordinary microscopic 

 methods. Their presence in smears is best demonstrated by the 



Indian ink method and in 

 tissue sections by the silver 

 impregnation method. 



Cultivation. Schereschew- 

 sky was the first to cultivate T. 

 pallidum artificially, although 

 never in pure cultures. In 

 1911 Noguchi obtained the 

 organisms from syphilitic 

 lesions and succeeded in culti- 

 vating them in the following 

 manner. The medium em- 

 ployed consisted of one part 

 of ascitic or hydrocele fluid and two parts of 2 per cent agar to 

 which was added a small piece of sterile rabbit kidney or other 

 organ. The medium was covered by a deep layer of paraffin oil 

 in order that strict anaerobic conditions might be maintained, and 

 a stab inoculation with the material containing the spirochetes 

 was made through the oil into the medium beneath. After ten 

 days' incubation the spirochetes were found to have grown out 

 into the surrounding medium, while most of the associated organ- 

 isms remained along the needle track. Subcultures made from 

 the outgrowths finally resulted in a pure culture of T. pallidum. 



Pathogenesis. Infection, so far as known, never occurs among 

 the lower animals except as a result of inoculation with pure 

 cultures or material containing the human virus. By this means 

 investigators have recently succeeded in producing the disease 

 both in rabbits and monkeys. 



In man the disease is acquired by direct contact with infected 

 persons or things. It runs a chronic course, usually divided into 

 three stages, primary, secondary, and tertiary. The initial or 



