THE ORIGIN OF CANCER 225 



ation of localized tissues not freely subject to proteolysis by the 

 corpuscular enzymes. 



(7) Malignant neoplasms, or true cancer, where a localized 

 irritation or abrasion has cooperated with protein maladjustments 

 to cause a proliferation of epithelial, endothelial, or connective 

 tissues constituting a more or less conspicuous neoplasm the tis- 

 sues of which are to some extent subject to hydrolysis by the 

 corpuscular enzymes. Here the development of the neoplasm 

 in itself evidences the disturbed conditions of protein metabolism 

 in the body (deficiency of corpuscular enzymes), and the new 

 cells tend further to disturb that maladjustment by presenting 

 additional protein material for hydrolysis. 



I am fully cognizant that so revolutionary a definition and 

 classification as the above, in which it is suggested that the can- 

 cerous condition is not necessarily associated with the presence 

 of such a neoplasm as is commonly supposed to constitute the 

 essentials of the disease, must excite surprise and opposition. But 

 I venture to believe that the more closely the matter is consid- 

 ered, the more valid will seem the reasoning on which the inter- 

 pretation is based. It will appear presently that there is also an 

 important body of clinical evidence that gives support to the view 

 above presented. 



SECTION II 

 THE ORIGIN OF CANCER 



What I have to suggest as to the origin of cancer follows as a 

 matter of course from the theory just outlined as to the nature 

 of the disease. 



Whatever tends to disturb protein metabolism in the body may 

 be considered as a predisposing cause of the malady. Familiar 

 causes of such disturbance are (1) lack of exercise, (2) excess 

 of protein food, particularly of animal proteins, (3) inadequacy 

 of the protein intake. 



It is obvious that the second and third of these causes of pro- 

 tein maladjustments are mutually exclusive. They must both 

 be borne in mind. An excess of proteins in the diet, resulting 

 in a putrefactive mass in the bowels and the entrance of a cer- 

 tain amount of unbroken protein into the parenteral system may 

 overwhelm the blood corpuscles and produce an anaemic condi- 

 tion comparable to that due to a lack of adequate protein for the 

 building up of fresh supplies of blood corpuscles. 



It will be recalled, of course, that there is constant destruction 

 of the red corpuscles in the spleen and liver, through which 



