56 Society for Experimental Biology and Medicine. 



walking. At one point the hair had been scratched off and the 

 skin bared but the tumor was not ulcerated. On removing, there 

 was no evidence of hemorrhage and a solid tumor about the size 

 of a hickory nut and weighing about 4 grams was taken out. It 

 had become attached to the skin but was apparently not attached 

 elsewhere. A piece of the tumor weighing about 1 y£ gram was 

 ground up with normal salt solution (3 c.c. normal salt to 1 gram 

 of tumor material) and this was injected under the skin of the neck 

 in twelve white mice. The remainder was fixed in 10 per cent, 

 formalin and in Zenker's fluid. No tumor has yet appeared in the 

 inoculated mice. 



Dr. Ewing described the tumor from sections as an adenoma 

 with glandular characters of the thyroid. Necrotic areas are few 

 in number and very small ; mitotic figures are rare. 



Sections of the tumor put through the Levaditi silver nitrate 

 method reveal the presence of Spiroclncta microgyrata. The 

 spirochete is not widely distributed but may be found at various 

 points in the tumor mass, especially in the few small vacuolar areas. 

 It has the characters of the species described by Lowenthal in 

 1905 in a case of human ulcerated carcinoma. It varies in length 

 from three to eight microns and has from four to thirteen turns or 

 " nodes," the average length of a node being six tenths of a micron. 

 The undulations are steep and closely pressed as indicated by the 

 specific name microgyrata. In view of certain minor differences in 

 staining power and habitat, I have given this organism a new 

 variety name. 1 



This is the tenth primary mouse tumor in which Spiroclucta 

 microgyrata has been observed. The first in which it was described 

 was a tumor in a mouse from Granby, Mass. In that tumor the 

 spirochetes were much more numerous than in the tumor now de- 

 scribed ; the necrotic areas of the former tumor mass were more 

 extensive and much more numerous than in our tumor and it had 

 more of the characteristics of carcinoma than ours. 



In all primary tumors the spirochetes are much less numerous 

 than in the transplanted tumors of the Jensen scries. In the latter, 

 especially in those strains giving a yield of 80 per cent, to 90 per 

 cent, on inoculation, the tissues arc fairly riddled with these spiro- 



1 Sec Journ. of Jnf. Diseases, March, 1907. 



