MALIGNANCY 37 



We are not going beyond what is known of repair if we say 

 that the reaction tissues are mainly connective. In the 

 normal gravid uterus the erosive action of the trophoblast 

 is thus in all probability stayed by a connective-tissue 

 reaction. Yet this erosive action is malignancy. Cells in 

 contact with the trophoblast dissolve — are, as it were, 

 digested. As the larva of the blow-fly dissolves dead cells, 

 so the trophoblast cap dissolves live uterine cells, by some 

 chemical product, some cytolitic secretion. In normal 

 gestation such action is neutralized sooner or later, and 

 since malignant epithelium, when active, pierces connective 

 tissues as if they did not exist, the reaction which stays 

 its course in the uterine wall must be more than mere 

 fibrous growth. We seem compelled to assume that some 

 cells can neutralize malignant cytolitic action by their 

 products, and thus restore physiological balance. The 

 resumption of pathological action in chorion-epithelioma 

 comes on in the period of involution, when all the uterine 

 tissues lose their activity. It seems hardly too much to 

 say that the secretions or cell-products of the active con- 

 nective tissue are those which inhibit, or fail to inhibit, 

 the alien epithelium. H. B. Spencer, after quoting Sir 

 John Williams, who stated that pregnancy had no influence 

 in causing benign ovarian tumours to become malignant, and 

 that in old women such are rare, goes on to say that the 

 cause of this rarity cannot at present be stated. A light 

 is, however, thrown upon these facts if it is remembered 

 that during gestation and the retrocedence of the aged 

 ovary there is great connective-tissue activity. 



If the implications of the argument are clear, it will be 

 seen that the conclusion to be drawn tentatively is that in 

 such reactions lies hidden the mystery of malignancy. 

 It will, perhaps, be objected that the multi-nuclear cap of the 



