Specific Organism 



773 



it is of interest to know that Wood* has been able to collect nine 

 such cases from the literature. 



Specific Organism. — The cause of the disease was unknown until 

 the discovery of Treponema pallidum, which opened a way for its 

 investigation. Castellani* was quick to seize the opportunity, and 

 in the same year in which Schaudinn and Hoffmann discovered 

 the cause of syphilis, announced a similar organism as the cause 

 of yaws. At the time of discovery he called it Spirochseta pertenuis 

 and Spirochaeta pallidula, but it is now recognized as a treponema 

 and is called Treponema pertenue. 



Morphology. — The organism so closely resembles Treponema 

 pallidum that it is rather by knowing the source from which the 

 organism was derived than by any morphologic distinctions that 



Fig. 304.— Yaws (photograph by P. B. Cousland, M. B., Swatow, China). 



the two are separated. It is said to be a little shorter than T. 

 pallidum, measures 7 to 20 ^ in length, is closely and regularly coiled, 

 and is said to have rounded ends. 



Staining. — ^It stains like its close relative, palely with most of 

 the dyes. The silver nitrate, the India ink methods, and the 

 other methods of staining Treponema are all appropriate, both for 

 demonstrating it in smears from the lesions or in sections of tissue. 



Cultivation. — The organism seems not yet to have been cultivated. 



Pathogenesis. — Castellanif has succeeded in infecting monkeys 

 with the scrapings from yaws papules. The infection usually re- 

 sulted in a local lesion, though there was also a generalized infection, 

 for he found treponemata everywhere in the lymph-nodes. When 

 the inoculation material was filtered and all of the organisms re- 



*"Brit. Med. Jour.," 1905, 11, 282, 1280, 1330. 

 t "Jour, of Hygiene," 1907, vii, p. SS8. 



