THE STUDY OF CANCER 25 



a transplanted tumour is growing proceeds only from the con- 

 sequences of growth, and the demands made for nutriment; 

 but as a rule the mice look quite well, and malnutrition 

 progressing to wasting is an occasional and accidental 

 occurrence. 



Thus far I have considered only the growth of cells, but 

 we have to deal with the growth of tumours often weighing 

 nearly as much as a mouse. If cell nutrition is so important 

 it may seem strange to say that the mice usually enjoy perfect 

 health. It was necessary to ascertain if the nutritive balance 

 in an animal had been disturbed by the presence of a tumour 

 in any other way than could be indicated by ill-health and 

 wasting. When very young mice are made to bear rapidly 

 growing and large tumours, they often only attain about half the 

 weight of others of corresponding age. When adult animals 

 bear rapidly growing and large tumours they may lose weight, 

 and more than is accounted for by the weight of the tumour. 

 This they speedily make good when the tumours are removed, 

 and the mice then revert to the normal conditions without any 

 detectable sign of their having ever borne tumours. The 

 gastric contents of normal mice after successful inoculation 

 with tumours contain a large excess of HC1 during active 

 digestion, as observed by Cramer and myself, and demonstrated 

 by Copeman and Hake, who have analysed the stomach contents 

 of over five hundred mice. This increase in HC1 is not to be 

 considered as out of accord with clinical observations in the 

 human subject. There is much evidence, recently added to by 

 the careful investigations of B. Moore, that the HC1 is diminished 

 in patients suffering naturally from cancer. I am at present 

 considering the facts on the growth of cancer in normal mice. 

 We require more data regarding mice spontaneously affected 

 with cancer. The contradiction between the state of affairs in 

 normal mice artificially made to bear tumours, and patients 

 bearing them naturally, reinforces the warning I have expressed 

 already. The conditions of the growth of cancer are to be 

 sharply distinguished from the conditions of origin, and I have 

 also pointed out that the conditions of growth in mice naturally 

 cancerous, and in normal mice, differ from one another. The 

 contradiction above referred to is probably only apparent, and 

 when it is resolved we may know much more of the deeper 

 significance of the diminution in HC1 in those spontaneously 



