INDIRECT EFFECT OF X-RAYS ON THE JENSEN-SARCOMA 



753 



measurement of the volume of the sarcomas, the vohmie must amount 

 to 1 cm^ or more. Such sarcomas exhibit a smaller increase in volume 

 in the later phases of the experiment than in the earlier ones. Table 8 

 shows the results of volume measurements which were performed on 

 two sarcomas placed at a far distance (8 cm) from each other. It is 

 evident from the table that the two sarcomas exhibit very nearly the 



Table 11. — Summary of the Rk.sults of Volume 

 Measitiements on Irradiated and Unirradia- 

 ted Sarcomas (one of the two sarcomas was 

 irradiated, the other shielded) 



No. 



Mean daily percentage increase in volume 



Before 



During 



After irradiation 



(A) Irradiated sarcomas 



27.6 

 46.2 

 7.2 

 32.2 

 39.1 

 44.2 

 44.6 

 19.5 



32.6 



same behaviour during the irradiation time. In the course of the first 

 8 days after irradiation and also in the next 6 days, the irradiated sarcoma 

 grows at only about one-half the rate of the shielded one. Since the 

 accuracy of measuring the volume of the sarcoma is limited, we base 

 our conclusions not on a single value for the increase but on the average 

 of the volume measurements made in a period of time (e.g. 6 days). 

 The collected results from fifteen similar experiments is seen in Table 9. 

 It is evident from Table 9 that the volume increase of the shielded 

 sarcoma during the irradiation period is not substantially different 



48 Hevesy 



