236 



Messrs. W. E. Bullock and W. Cramer. 



getting strictly comparable sets of birds. The laboratory conditions with 

 strict control of diet and proper collection of excrement are not very suitable 

 for keeping birds in health for a prolonged period. One of us is, however, 

 extending his observations to the study of growing rats, which can be much 

 more suitably reared and controlled, and hopes shortly to.be able to publish 

 an account of his experiments. 



The results given in this paper, however, taken in conjunction with the fact 

 that, in the differentiation of the ovum into the complex aggregate of cells 

 constituting the chicken, no formation of cholesterol takes place, appear 

 to support the view formerly expressed that cholesterol is not readily 

 synthesised in the organism. 



We take this opportunity of expressing our thanks to the Government 

 Grant Committee of the Koyal Society for assistance in carrying out this 

 work. 



Contributions to the Biochemistry of Growth.*— On the Lipoids of 

 Transplantable Tumours of the Mouse and the Rat. 

 By W. E. Bullock and W. Cramer. 



(Communicated by Sir John Bradford, Sec. R.S. Received October 1, — 

 Read November 20, 1913.) 



(From the Chemical Laboratory of the Physiology Department, Edinburgh University, 

 and the Imperial Cancer Research Fund, London.) 



The following observations were carried out with the object of obtaining 

 information concerning the presence of lipoid substances in rapidly growing 

 cells. Our observations were made on transplantable tumours of mice and 

 rats, which, as we have pointed out in previous papers of this series, are 

 especially suitable for the study of the biochemical problems of growth. So 

 far as we are aware, neither qualitative nor quantitative observations on the 

 presence of lipoids in these tumours have as yet been made. 



The analytical method employed was the same as the one used in our 

 observations on normal and degenerating nerves.f The fact that by means 

 of this method 99 to 101 per cent, of the total lipoids present in normal 



* This research is in continuation of papers in ' Roy. Soc. Proc.,' B, 1908, vol. 80, 

 p. 263 ; 1910, vol. 82, pp. 307 and 316 ; 1913, vol. 86, p. 302. 



t Cramer, Feiss and Bullock, ' Proc. Physiol. Soc.,' 1913, p. li, ' Journ. Physiol.,' vol. 46. 



