166 APPLICATION TO CANCER RESEARCH 



metastases in other parts of the body. Still, the fact re- 

 mains that metastases occur only in malignant disease. 



The foregoing points formed our axioms. Whatever 

 experiments we undertook had to harmonise with them 

 all in their consideration. There was one other factor, 

 however, which has already been mentioned; the mys- 

 tery of the cause of cell-division in the body, and a 

 well-known predisposing factor in the causation of 

 cancer which is intimately associated with it, namely, 

 chronic irritation. 



The body consists almost entirely of living cells; 

 individual living creatures, each of which is capable of 

 separate existence for a short time, but which in con- 

 junction with one another form the tissues which in 

 their turn have special functions. Each cell is merely 

 an individual in a multitude; a unit in an organ. Cells 

 not only have functions to perform for their own 

 individual welfare, but they also act collectively for the 

 general welfare of the body. 



Since cancer consists of a tumour composed of cells, 

 we may attack the problem of its causation from two 

 aspects the investigation of the individual cells, and 

 the investigation of collective masses of them. At the 

 outset, the first aspect is obviously the one to receive 

 consideration; and since cancer consists of a growth of 

 cells which have multiplied too often and have so 

 formed a tumour, the first question to be asked is, 

 What makes this excessive multiplication take place ? 



Before this question can be approached, however, 

 another question must be answered, namely, What 

 makes any multiplication of cells take place ? 



