332 On the Origin of Cancer Cells 



Tabel 1. Contrast of theQ values of some normal body with cells the Q values 



of ascites Cancer cells. 



Cells Qoo <2mN 2 Qatp° 2 QatpN 2 Qatp0 2 + QatpN 2 



An example of the latter type of confusion is involved in the discussion by Albert 

 Fischer 34 , especially in the chapter "Energy exchange of tissue cells cultivated in 



vitro." 



Rous agent. If the Rous agent is inoculated into the chorion of chick embryos, 

 tumors originate in the course of a few days — as rapidly as in the transplantation of 

 cancer cells. The tumors formed are not chorion tumors but Rous sarcomas. The 

 Rous agent, to which a particle weight of 150 million is ascribed at present, is 

 therefore capable of transmitting the morphological properties of the Rous sar- 

 coma; and whatever we call the Rous agent — "hereditary unit", cell fragment, 

 microcell, or spore — the transmission of the Rous sarcoma by the Rous agent is, 

 in any case, nothing more than a transplantion and is to be differentiated strictly 

 from the production of a chicken sarcoma by methylcholanthrene, which is a neo- 

 formation of a tumor from normal body cells and as such takes a long time. 



The metabolism of the chicken sarcomas, whether produced by the Rous agent 

 or by methlycholanthrene, is the same and does not differ in any way from the 

 metabolism of the tumors of other animals 35 . In the first case, however, the fer- 

 mentation potential has been transplanted with the Rous agent, whereas in the 

 second case the fermentation has been intensified by selection from normal body 

 cells under the action of the methylcholanthrene. 



Addendum: in vitro Carcinogenesis and Metabolism 



Since this paper was prepared, striking confirmation and extension of its main con- 

 clusions have been obtained from correlated metabolic and growth studies of two 

 lines of tissue culture cancer cells of widely differing malignancy that were both 

 derived from one and the same normal, tissue-culture cell 36 . The single cell was 

 isolated some 5 years ago from a 97-day old parent culture of normal subcutaneous 

 adipose tissue of a strain C3H/He mouse by Sanford, Likely, and Earle 33 of the 

 National Cancer Institute. Up to the time that the singlecell isolation was made, no 

 tumors developed when cells of the parent culture were injected into strain C3H/ 

 He mice. Injections of in vitro cells of the lines 1742 and 2049 (formerly labeled 

 substrains VII and III, respectively) first produced tumors in normal C3H/He 

 mice after the 12th and 19th in vitro transplant generations, respectively; after 

 l 1 /2 years, the percentage production of sarcomas was 63 and Opercent, respectively; 

 and after 3 years, it was 97 and 1 percent, respectively, with correspondingly 

 marked differences in length of induction period. Despite such gross differences 



