MALIGNANCY 41 



on as highly unstable because of these very qualities. But 

 its instability is obviously a function of many variables. 

 From the universal presence of these two tissues we infer 

 that normally there is nothing in the organism which 

 inhibits the existence of either in any part. They can grow 

 anywhere, and if aberrancy occurs at all it is in them we 

 should look for it, if they did not, in some analogous to the 

 action of the endocrines, inhibit each other's undue growth. 

 The age incidence of sarcoma and carcinoma suggests most 

 forcibly that they do so. Sarcoma is predominately a 

 disease of youth, though it may be found at any age. It may 

 develop in utero. Repair is most active when it is com- 

 monest, and epithelium is most delicate. Epithelium 

 reaches a peculiar state of activity, as shown by its 

 products and conduct, at a later age in which connective- 

 tissue activity is lessened and repair slackens. It is a period 

 in which persons of failing metabolism tend to accumulate 

 toxic products in the connective tissue which depress and 

 inhibit its activity. It is the age of cancer. When cancer 

 occurs in the adolescent there is frequently a history of 

 heredity. That the unbalanced should breed unbalanced 

 offspring is not surprising. The cancer house and the 

 cancer valley are unhealthy, most low-lying. From a defec- 

 tive environment we do not expect tissue health or balance, 

 i.e. the normal influence of one tissue on another in a 

 federated system. It is by no means necessary that such 

 influences must be exerted by definite glands. Every glan- 

 dular secretion is but a specialized form of some unknown 

 epithelial product. Snake venom arises in a specialized 

 salivary gland; the secretion of the salivary gland in 

 embryonic epithelial cells. Epithelium as the parent tissue 

 of the true glands must have its own unspecialized secre- 

 tion, which is poured into the circulation and exerts its 



