1910.] Contributions to the Biochemistry of Growth. 



315 



tlie protein metabolism. The tumour cells do not proliferate at the expense 

 of the tissues of the host, nor is there any evidence that they have a higher 

 affinity for nutritive material than the growing cells of the host. 



4. There is no evidence of the existence of substances secreted by the 

 tumour disturbing the nitrogenous metabolism by means of a toxic action on 

 the tissues of the host. 



5. It is specially pointed out that these conclusions refer only to animals 

 bearing tumoui's of sufficient size to warrant the assumption that they would 

 reveal any specilic property or function which may be possessed by the cells 

 of a neoplasm. The effects which a large tumour must necessarily produce 

 by virtue of its mere mass are not here considered. 



The expenses of this research have been defrayed by grants from the Moray 

 Research Fund of the University of Edinburgh. 



Contributions to the Biochemistry of Growth..^ — Distribution of 

 Nitrogenous Substances in Tumour and Somatic Tissues. 

 By W. Ckamer and Harold Pringle. 



(Communicated by Prof. E. A. Schafer, F.R.S. Received February 3,— 

 Read February 24, 1910.) 



(From the Physiology Department, University of Edinburgh, and the Imperial Cancer 



Research Fund, London.) 



In the preceding paperf a determination of the distribution of the 

 nitrogen retained during a metabolism experiment showed that less nitrogen 

 is needed to build up a given weight of tumour tissue than is necessary 

 to build up an equal weight of the somatic tissues of the host. If 

 this result is correct, it would follow that cancerous tissue should have 

 a lower nitrogen percentage than the somatic tissues of the host. 



We have therefore carried out nitrogen estimations of various tissues of 

 Rats I, II, and III used in the experiments described in the preceding paper. 



In order to make our results applicable to carcinomatous tumours, we 

 examined the tissues of mice of about the same age, bearing a rapidly growing 



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

 p. 263, and this vol., p. 307, supra. 



t W. Cramer and Harold Pringle, ' Roy. Soc. Proc.,' supra, p. 307. 



