1913.] Rays upon the Cells of Jensen's Rat Sarcoma. 485 



about eight days was followed by an almost equally rapid growth. For the 

 more prolonged periods 30 and 60 minutes, i.e. Series II and III respectively, 

 the initial reaction, resulting in easily measureable nodules, showed gradual 

 signs of absorption, until after 27 days there was every indication that 

 complete disappearance of the nodules would result. One rat of Series II 

 was killed at this stage, the small nodule was found to consist almost entirely 

 of sarcoma cells (vide Plate 12, microphotograph 1). 



Continued observations, however, showed that in three of the rats of 

 Series II, nodules remained palpable for a prolonged period and eventually 

 they developed into tumours. In Series III this occurred in one rat and 

 resulted in a fairly rapidly growing tumour. The gradual decline in size of 

 the initial nodules and the subsequent growth of the tumours are depicted 

 for each of these four animals in fig. 3. The full-line curve marked III 









o 



1 



1 



1 



1 











1 



1 



1 



i 







r 





1 











j f 





/ 









t 



ft: 



° DAYS 20 



40 



Co 



SO 



100 



Fig. 3. 



corresponds to the single occurrence in Series III and the dotted curves to 

 the three rats of Series II. The nodules in the two remaining rats in 

 Series II disappeared after 24 and 81 days. On re-inoculation with 0T c.c. 

 of tumour emulsion the first was refractory and the second yielded a growing 

 tumour. 



