PREFACE 



THE following papers outline a continuation of 

 the results of the researches which were published 

 by me eight months ago in a book entitled Induced 

 Cell- Reproduction and Cancer. 1 



The book described a method by which it was 

 found that human white blood-corpuscles and other 

 cells can be made to divide when they are absorb- 

 ing certain chemical agents from a film of jelly 

 set on a microscope slide. The chemical agents 

 evidently cause the divisions; and this fact formed 

 the basis of a theory as to the possible causation 

 of benign and malignant growths within the body, 

 and led to the elaboration of experiments to try 

 to prove the theory in question. 



I was fully aware when I wrote it that the 

 book was compiled in rather an unusual manner, 

 and that the results which it mentioned were 

 revolutionary to the older ideas ; but it described 

 a new method of research which has undoubtedly 

 revealed new facts ; and I considered that the way 

 in which it was written might render the details 

 of the complex experimental methods more read- 

 able, and facilitate their consideration which I 

 think it has done. Unfortunately, a group of 

 gentlemen, whom I had thanked in the preface 



1 London, John Murray, 1910. 

 1* 5 



