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Contnbutions to the Biochemistry of Growtli r'—The Total Nitrogen 

 Metabolism of Rats hearing Malignant Neiv Groivths. 

 By W. Ckame[{ and Harolu Pringle. 



(Communicated by Prof. E. A. Schafer, F.RS. Received Januai-y 25,— 

 Read February 24, 1910.) 



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



Research, London.) 



The following experiments were carried out with the object (1) of studying 

 the effect of a rapidly growing neoplasm on the metabolism of the normal 

 animal which bears the tumour, with consideration also of the view that the 

 new growth secretes, as has often been asserted, substances having a 

 deleterious action on the tissues of the animal bearing the tumour ; (2) of 

 elucidating the processes determining the rapid proliferation of the cells of a 

 malignant new growth, and the source of the nitrogenous material used by 

 the tumour. 



In order to obtain facts throwing light on these questions, we have deter- 

 mined the nitrogenous metabolism in three rats before and after implantation 

 of a rapidly proliferating malignant new growth. So far as we are aware, no 

 such experiments have been made before. 



The tumour used for these experiments was a spindle-celled sarcoma of 

 very rapid growth, obtained from the Imperial Cancer Research Fund 

 (tumour J. R. S.). This tumour can be transplanted with a high percentage 

 of success in young animals of 40 to 60 grammes weight ; with older rats of 

 over 100 grammes weight the percentage of progressively growing tumours is 

 not so high, and preliminary transient growth occurs more frequently. Since 

 young growing rats did not appear to be suitable for a metabolism experiment 

 in which it was desirable to obtain a constant nitrogen output, we found it 

 necessary to use older animals. 



Three rats of about the same age and weight were kept on a constant diet 

 of a uniform composition. The diet used consisted of 56 grammes of stale 

 bread made into a pulp with 50 c.c. of milk. Of this pulp 40 grammes were 

 given to each animal in two daily rations. When a constant nitrogen output 

 had been obtained, the rats were inoculated with a measured dose (0"1 c.c.) of 

 the tumour, and the observations continued for the succeeding 15 days. At 

 the end of the first week tumours could be distinctly felt. On the 16th day 

 after transplantation the rats were killed. One animal (Rat I) had developed 



* This reseaix'h is in continuation of paper in ' Roy. Soc. Proc," E, vol. 80, 1908, p. 263. 

 VOL. LXXXII. — B. 2 C 



