22,3 Sellards and Goodpasture: Immunity in Yaws 235 



months, developing usually metastatically, though occasionally 

 perhaps by direct accidental inoculation. 



The material for the first inoculations was secured by remov- 

 ing the yellow crust from a well-developed yaw and scraping 

 the surface firmly with a scalpel. The exudate thus obtained 

 always contained a moderate amount of blood, and no precautions 

 were taken to insure the removal of visible pieces of tissue. 

 Smears of this material were subsequently stained by Giemsa's 

 method. Usually treponemata were very scanty. Observers 

 frequently speak of the very abundant spirochetes seen in 

 smears from yaws nodules. We have not found spirochetes in 

 large number except secondary invaders, distinct from the 

 causative treponema. This material was reinoculated imme- 

 diately in an incision through the skin, made sufficiently deep 

 to cause a slight oozing of blood. The skin over the deltoid 

 muscle was selected for the site of inoculation, since this area 

 is not ordinarily involved spontaneously. The work was con- 

 ducted under dispensary conditions, and it was not feasible to 

 make observations oftener than at intervals of one week. The 

 details are as follows: 



In the first case the disease was of two months' duration at 

 the time of reinoculation, the mother yaw being present and 

 active. There was also a generalized papular eruption over the 

 trunk and the lower extremities. The inoculations were made 

 in three incisions. A week later they had healed completely. 

 Observations were continued for a period of six weeks, and no 

 changes occurred at the site of inoculation. In the meantime, 

 however, typical multiple granulomata developed elsewhere over 

 the body. The patient was given neosalvarsan. 



The second case had developed a mother yaw five months 

 previously and now showed five secondary granulomata. Three 

 incisions in which the inoculations were made healed promptly 

 and remained entirely negative during the six weeks' period 

 of observation. Treatment with neosalvarsan was commenced. 



In the third case the disease was of four months' duration, 

 the mother yaw being present. One month after its appearance, 

 the patient was vaccinated against smallpox and a typical 

 granuloma developed at the site! of this vaccination. Numerous 

 papules also appeared over the face and the body; several 

 developed into typical granulomata. Material from one of 

 these was reinoculated into three incisions of the skin over the 

 deltoid. The incisions healed promptly; during the next six 

 weeks some additional granulomata developed but none appeared 



