434 STRONG. 



but on the parts of the body where the epidermis is thick, such as the soles of the 

 feet, it may persist for much longer periods. 



Scheube believes that the duration of yaws varies between a few weeks and 

 several years, and that the treatment, food and hygienic condition of the patient 

 influences the time. 



According to Castellani, unless the disease becomes extinct after the secondary 

 stage, it may extend to many years. Jeanselme states that framboesia runs a 

 chronic course varying from several weeks or months to a number of years. 

 Firth describes yaws as a chronic disease, the secondary eruption lasting from a 

 few months to two years. 



THE SPECIFIC CHARACTER OP YAWS. 



It is not my intention here to enter into a prolonged discussion of the 

 question of the specificity of yaws as a disease. Almost all observers 

 agree that it is not identical with syphilis. Sheube and Firth are 

 inclined to support the original idea of Hutchinson that yaws -was the 

 original disease from which European syjDhilis has been evolved or that 

 the two diseases developed from a parent form, each having been modified 

 by being propagated by different races in different climates. Manson, 

 Castellani, Jeanselme and Plehn regard them as specifically distinct. 



I have had abundant opportunity for the observation of all forms of 

 yaws in several tropical countries for a number of years and my own 

 opinion, based largely upon clinical material, histologic examinations, 

 experiments in inoculation and serum reactions carried on in this lab- 

 oratory, as well as upon the experimental work of others, is strongly in 

 favor of the view that yaws and syphilis are distinct. 



I believe that while the two diseases are certainly closely related from 

 an etiologic standpoint, yet they are different affections. Since the 

 discovery of the specific organism of yaws, Treponema pertenuis, by 

 Castellani in 1905, a number of observers have carried on comparative 

 morphologic studies between this organism and Treponema pallidum. 



Prowazek, Blanchard, Martin and Levaditi have discussed the slight morpho- 

 logic differences between these organisms; these however are not sufncienth 

 constant or definite to serve as a means of differentiation. On the other hand, 

 inoculation experiments, both in man and animals, appear to have resulted in a 

 more definite distinction. Charlouis in 1881 inoculated a native suffering from 

 typical yaws, with syphilis. A primary indurated syphilitic chancre developed, 

 and a typical secondary syphilitic eruption followed. This experiment apparently 

 has not been repeated in man, although a number of observers, Bestion, Powell, A. 

 Nicholls and others, have reported cases of yaws which subsequently have con- 

 tracted syphilis. 



Neisser, Baermann, Halberstiidter, and Castellani have shown that monkeys 

 successfully inoeulated with framboesia do not thereby become immune to syphilis, 

 and subsequently may be infected with the latter disease and vice versa, apes 

 successfully inoculated with syphilis remain susceptible to framboesia. Halber- 

 stiidter also believes the appearances of the primary inoculative lesion in lues 

 and framboesia to be different. All of these authors conclude from their experi- 

 ments that the two diseases are etiologically distinct. 



