754 



ADVENTURES IX RADIOISOTOPE RESEARCH 



from that of the unshielded one (ratio 1.3). In the 8 subsequent days, 

 on the contrary, as also in the next 6 days, the ratio is nearly equal 

 to 3. A still greater ratio is obtained by comparing the values for the 

 third (7 day) period of the experiment. In the last time interval, how- 

 ever, only a few measurement are available since volume measurements 

 during this time were either impracticable or insufficiently accurate. 



Table 12. — Comparison of the Increases in Volume of the Two 

 Sarcomas in Unirradiated Rats 



(Inoculated 3 November, 1943; a-anterior sarcoma, b-posterior sarcoma) 



The results of another series of experiments are shown in Tables 10 

 and 11. The sequence of one experiment is recorded as an example in 

 Table 10. Table 11 contains the summary of eight experimental se- 

 quences. 



If we consider, on the other hand, the average value of the eight ex- 

 periments recorded in Table 11 the increase during irradiation in the irra- 

 diated sarcoma is indeed only slightly le^s than in the unirradiated one, 

 but during the following 5 — 6 clays the volume increase in the irradiated 

 sarcoma amounts only to about one-third of that occurring in the unir- 

 radiated growth. Therefore, we find the same result as in the case of the 

 experimental series at first discussed. 



