EFFECT OF X-RAYS ON NUCLEIC ACJJJ IX JENSEN-SARCOMA 



71 



of nucleic acid was obtained from the radioactive measurements within 

 about 3 per cent. A very substantial fraction of the radioactively labelled 

 nucleic acid must therefore be ascribed to the growth process. 



Effect of X-rays on the Formation of Acid-Soluble Phosphorus Compounds 

 in the Sarcoma 



In contrast to tlie synthesis of nucleic acid molecules, the formation 

 of acid-soluble phosphorus compounds in the sarcoma is not noticeably 

 affected when exposed to a dosage of a few thousand roentgens, as is 

 shown in Table 13. 



Table 13. — Formation of Radioactively 



Labelled Acid-Soluble Phosphorus Compounds 



IN THE Irradiated Sarcoma 



It is evident from Table 13 that the 7-min fraction has nearly- the 

 same specific activity as the 0-min fraction, and that the bulk of the 

 remaining fractions is also radioactively labelled, i. e. it has been newly 



