Prevention of Syphilis in Macacus Rhesus. 91 



The experiment which I wish to report was made upon five Macac 

 monkeys. They were all inoculated over both eyebrows with 

 scrapings from a syphilitic papule of the tongue which had been 

 shown by the dark field illumination microscope to be rich in living 

 SpirocJieta pallida. Two of the monkeys remained as controls 

 and the other three received o. 1 5 gram atoxyl subcutaneously, 

 one day, eight days and fifteen days respectively after the inocula- 

 tion. Only the two controls developed specific lesions. Three 

 months later two of the atoxyl-treated monkeys (one having died 

 in the interim) and another control monkey were inoculated over 

 the right eyebrow with virus from a primary syphilitic lesion rich 

 in SpirocJieta pallida. Within three weeks one of the atoxyl-treated 

 monkeys and the control monkey developed specific lesions, show- 

 ing the pallida, over the right eyebrow. 



This experiment is an example of the power which atoxyl pos- 

 sesses of suppressing the development of syphilitic lesions when 

 given as late as fifteen days after inoculation with active virus, and 

 indicates that this suppression is not attended with the production 

 of a state of immunity to the virus. 



53 (309) 

 Further notes on a rat tumor. 



By SIMON FLEXNER and J. W. JOBLING. 



\From the Rockefeller Institute for Medical Research^ 



On several occasions we reported to this Society upon a rat 

 tumor that has been transplanted for more than two years. The 

 tumor was originally described as a sarcoma. In a recent report 1 

 we described its transformation into a malignant adenoma. This 

 change in histological structure was attended with the acquisition 

 of the property, hitherto absent, of producing metastasis in lym- 

 phatic glands. The reverse changes, namely from the adenoma 

 into sarcoma, had been noted by Ehrlich, Leo Loeb and others 

 in mouse cancers and were attributed to gradual or rapid prolifera- 

 tion and predominance of the stroma of the tumors or of a cor- 

 responding tissue derived from the host. Since our rat tumor 



1 This journal, 1908, v, p. 52. 



