22,3 Sellards and Goodpasture: Immunity in Yaws 245 



started. On reinoculation, slow-growing granulomata developed 

 at each of the two incisions, and after three weeks spontaneous 

 regression set in. The larger of the two lesions was excised 

 and, subsequently, numerous small granulomata appeared at the 

 site of excision, excited perhaps by the surgical trauma. The 

 lesion which was left undisturbed disappeared completely. In 

 the other two patients the infection had persisted for more than 

 a year, and the mother yaw had disappeared completely when 

 the injections of neosalvarsan were given. Both of these patients 

 developed abortive lesions which disappeared promptly. 



Of the many possible interpretations of these results it seems 

 plausible to us that these abortive reactions are due to an 

 active immunity and are analogous in a general way to the im- 

 mediate temporary reaction following the vaccination of indi- 

 viduals immune to smallpox. Indeed, it is the only example 

 with which we are familiar of an abortive reaction developing 

 with a virus for which the etiologic microorganism has been 

 established. It is often difficult to distinguish between active 

 immunity and latent infection resulting in a refractory state. 

 The latter assumption is not plausible in these cases of yaws. 

 The striking effect of neosalvarsan upon Treponema pertenue, 

 the prompt disappearance of the clinical manifestations, and 

 the gradual weakening or disappearance of the Wassermann 

 reaction are stuong arguments indicating the radical cure of 

 the disease. 



Our results throw some light upon the spontaneous course of 

 yaws. After the development of the mother yaw, successive 

 crops of secondary granulomata develop, for the most part by 

 metastatic infection. The Wassermann reaction becomes posi- 

 tive and, also, a measurable degree of immunity slowly develops. 

 This immunity is not sufficient to produce regression of the 

 granulomata already formed, but it seems to be effective even- 

 tually in preventing metastatic infection, thereby gradually 

 bringing about the termination of the secondary stage and, 

 frequently, of the disease itself. In other cases, latent foci of 

 infection persist in the bones and in the thickened epidermis 

 of the feet and hands, lasting for many years or throughout life. 



The question of recidives in yaws has often been loosely dis- 

 cussed from a clinical standpoint. It involves two aspects; 

 namely, (a) whether a patient in the late or tertiary stage of 

 yaws may suffer a recrudescence of the typical secondary or 

 granulomatous stage, and (b) whether a patient actually cured 

 of the disease and free of treponemata may experience a typical 



