THE ORIGIN OF CANCER 227 



should always receive careful attention from the physician. Any 

 condition that causes persistent anaemia should be viewed with 

 solicitude in this connection. 



A greater or less degree of instability conditioned on heredity, 

 is implied as a matter of course, as determining a "tendency" to 

 cancer. Hormone disturbance (e. g., thyroid inefficiency) may 

 also constitute a predisposing element. 



As to causes that determine the localized development of a 

 neoplasm, when the cancerous condition eventuates in such 

 development, elaborate studies have been made, and there is vir- 

 tual unanimity of opinion among authorities. Any chronic source 

 of irritation may result and indeed must result in stimulus to 

 growth of new cells. A callous on the thumb and a corn on the 

 toe illustrate this principle as tangibly as an epithelioma on the 

 lip where a clay pipe has long been held, or a carcinoma of the 

 breast that developed from a nipple irritated by a corset steel. 

 But the thumb callous and the corn are "benignant" growths 

 because their tissues are not of a character to be broken down 

 by the bodily enzymes. The same is true of an ordinary 

 overgrowth of fibrous tissue in the interior of the body, as a 

 fibroid of the uterus or a fibroma located, for example, on the 

 forearm. 



The new growth, let it be emphasized, becomes malignant only 

 when its character is such that its cells can to some extent be 

 hydrolyzed by the bodily enzymes (including, prominently, ac- 

 cording to present thesis, the enzymes of the white and red cor- 

 puscles). Moreover, even cells falling within this definition are 

 not necessarily a menace to the system, provided the supply of 

 enzyme- forming corpuscles is adequate and in good working 

 order ; for in that case misplaced new cells are at once dissociated 

 and the products of such dissociation utilized as animo-acids or 

 eliminated from the body. According to the proteomorphic 

 theory, the early stages of such dissociation are effected by the 

 white corpuscles, and the later (polypeptid) stages by the red 

 corpuscles ; but details as to this are not essential to the present 

 thesis. What is essential is the recognition that if the enzymes 

 that are competent to hydrolyze cells, whenever these cells are 

 present in excess, are normally abundant in the system, there will 

 be no development of a malignant neoplasm. 



Stated otherwise, the presence of the tangible "malignant" 

 neoplasm is in itself evidence that there was antecedent disturb- 

 ance of the processes of protein metabolism in the body, charac- 

 terized specifically by inadequacy of the enzymes that deal with 

 proteins not needed by the system. 



Viewed from a slightly different angle, it appears that any 

 proliferation of new cells, however induced e.g., in repair of an 



