APPLICATION TO CANCER RESEARCH 11 



there are doubtless many more to come. The feeling of 

 astonishment may be imagined when one of us for the 

 first time and the cells have been discovered for more 

 than a century saw most of the polynuclear leucocytes 

 in the specimen in the act of divisron. It was expected, 

 it is true; but the way in which these cells divide was 

 by no means expected. 



We have carefully searched the literature relating to 

 our subject, without discovering points which have 

 helped us. Most of the literature is devoted to de- 

 scriptions of morphology which are not of much 

 assistance in this kind of experimental work. There 

 is no literature dealing with the effects of chemical 

 substances on stained, individual, living human cells, 

 and if a point is to be unravelled we have found it 

 better to make experiments for its solution rather 

 than to depend upon any literature dealing with the 

 observation of dead cells. 



The new investigator will have to begin at the 

 beginning, which is not far off, and he will have to 

 do so with an open mind. 



The foregoing points indicate briefly the scope of 

 this book descriptive of the new methods, and of the 

 paths of research which have been opened by them. 

 But we shall also describe in detail the main path 

 which we have followed namely, the adoption of the 

 methods for the elucidation of the cause of cancer. 

 It must be obvious that since we can now induce 

 proliferation in human cells, and since the proliferation 

 of certain human cells is the fundamental condition 

 which characterises cancer (for that is what it is), we 



