308 



Messrs. W. Cramer and H. Pringle. 



[Jan. 25, 



a large, progressively growing tumour (5"1 grammes). The second rat (Rat II) 

 had a smaller tumour (weighing 1"55 grammes) which was not increasing in 

 size, and which possibly would have undergone spontaneous absorption if 

 the experiment had been continued. In the third animal (Rat III) only 

 transient proliferation had taken place, and no tumour was found when the 

 animal was killed. Rat III may therefore serve as a useful comparison 

 while Rat I represents the conditions in an animal with a tumour following 

 its normal course of progressive proliferation. The cages in which the 

 animals were kept were similar to those used by Prof Schiifer* in his experi- 

 ments on feeding with pituitary substance. In these cages the urine and the 

 faeces can be collected separately. The ol)servations were made in periods of 

 three days. The food was given in high, narrow beakers, fixed in the cage, 

 a device which prevented the animals from spilling the food. The beakers 

 were removed empty after one hour. The animals rapidly ate all the food 

 given to them, and were in good condition throughout the experiment ; but 

 Rat III did not appear to be so lively during the last week of the experiment, 

 and was not so hungry at the time of feeding as the others, so that in the 

 last week the food had to be left in the cage during the whole day. We 

 have repeatedly noticed that where this tumour is being absorbed after a 

 rapid initial proliferation, the health of the animals appears to be affected. 



The food was analysed at different times duruig the experiment. It was 

 found to have a constant N percentage. Six duplicate analyses gave 

 1-08 grammes N as the amount of nitrogen given in the food (120 grammes) 

 during each three-daily period. 



The results obtained are given in Table I. 



It will be seen that the three animals continued to retain nitrogen and to 

 increase in weight after transplantation. During the first two or three periods 

 after the transplantation, when the absolute amount of tumour growth is 

 slight, and when the introduced cells are being provided witli a new stroma, 

 the nitrogen retention remained on a low level and the animals did not gain 

 in weight. But when the tumour had once established itself and was growing 

 rapidly (Rat I, periods from 8, VII to 1:3, VII), the nitrogen retention rose 

 rapidly. ■ It will l)e shown that this is due not only to tl)e fonnation of new 

 tumour tissue, but to the organism of the host itself retaining nitrogen and 

 increasing in weight correspondingly. The absorption of food from the 

 iiitestini;, as indicated by the nitrogen of the heces, remained about the same. 

 The urine was examined for crciitine during the lirst nine days after trans- 

 plantation. No creatine was i)reHent. 



* K. A. Schiifer, Croonian Lecture, "Tlic Fiiiietioim of tlic I'ituiUiry I'xxiy," ' Hoy. Soc. 

 IVoc.,' I'., vol. 81, 1f)0!), p. 442. 



