72 FUNCTIONAL INERTIA 



It is the nature of the foetal villi to burrow their 

 way through maternal tissues, but when, through 

 their functional inertia, they continue to perform 

 this burrowing after their growth should have 

 ceased they give rise to a malignant epithelioma. 

 Malignancy is thus related to protoplasmic inertia. 

 Professor Adami, both in his paper on " The Causa- 

 tion of Cancerous Growths" * and in a private com- 

 munication to me, acknowledges that what he had, 

 since 1896, called " habit of growth " in certain 

 cells which ought not to be prolif ei ating then or 

 there, is " based upon that principle of inertia " 

 concerning which he quotes from my first paper and 

 which he had first seen formally treated there. A 

 remark of Sir Lauder Brunt on' s is explicable in the 

 light of these considerations, " not disease itself, 

 but the tendency to it, is hereditary." t The 

 tendency as a molecular pre-adjustment in one 

 generation is by functional inertia carried over 

 into the next generation ; the acquirement of the 

 disease is the result of a specific stimulus (the 

 pathogenic micro-organism) acting on the indi- 

 vidual affectability (susceptibility) towards the 

 " infection." 



In connection with heredity we have the very 

 important subject of reversion to type of type- 

 stability, on which such a writer as Mr. Francis 

 Galton has a good deal to say. He thus expresses 

 himself, " Regression towards mediocrity in hered- 



* Adami, British Medical Journal, March 16, 1901, pp. 624-626. 

 t Brunton * " Croonian r Lecture." i 



