THE VENEREAL DISEASES 81 



which causes syphilis have extended over a long 

 period, and not until very recently has any definite 

 conclusion been agreed upon. Through a series of 

 experiments by Schaudinn and Hoffman, which were 

 confirmed by Metchnikoff and others, it has been 

 decided that syphilis is due to a spirillum known as 

 Treponema pallidum, the reasons 

 for the long delay in arriving 

 at a decision being the fact that 

 the organism is exceedingly 

 difficult to stain, and, without 

 staining, it is almost impossible FIG. ie. 



pallidum. 



to see it. 



For many years all efforts to cultivate Treponema 

 pallidum upon an artificial medium were unsuccess- 

 ful, although monkeys had been inoculated and from 

 the lesions other monkeys were successfully inocu- 

 lated, which seemed to be conclusive evidence that 

 Treponema pallidum undoubtedly caused syphilis. 

 Schereschewsky, a German bacteriologist, was the 

 first to bring about the growth of Treponema pal- 

 lidum on artificial media (1909). 



Syphilis is transmitted by sexual congress, may 

 be transmitted by a diseased parent, or may be 

 acquired by inoculation through an abrasion of the 

 skin or mucous membranes. 



