SOME CATALYTIC ASPECTS OF DISEASE AND DRUGS 235 



ering these experiments, Rous states in the American Scientist 

 (1946): 



"To account for these multifarious neoplasms by the localiza- 

 tion in the embryo tissues, before and after implantation, of tumor 

 viruses like those already known, each capable of producing neo- 

 plasms of but a single sort, one would have to suppose that a great 

 swarm of such agents circulate constantly in the blood of the 

 mother mice or those to which the tissue had been transferred, 

 and that they regularly lodge, each in the embryo cells suited to 

 harbor it. Nature is profuse and often does things in what seems 

 to be the hard way, yet the existence of such a state of affairs seems 

 beyond belief. So, too, with the possibility that a single source 

 virus reaches cells of every sort early in gestation, from then on 

 sojourning with them and becoming peculiar to them, and that 

 variants arise after awhile — if conditions are right — which mani- 

 fest the narrow specificity and limited scope of the viruses with 

 which we are acquainted. The milk factor can hardly be cited in 

 support of this conception of a widely disseminated and pluri- 

 potential source virus, since its localization and its effects are both 

 restricted to mammary tissue, while furthermore it is responsible 

 for but a single kind of tumor out of the number to which the 

 mouse mamma is liable. One is forced to conclude that the cells 

 of the embryo have an inherent capacity to undergo neoplastic 

 change." 



Every cell, embryonic or not, has enormous numbers of specific 

 molecules in extensive variety, and most kinds of cells may develop 

 neoplasms. Besides carrying the specific molecules responsible for 

 differentiation, the gametes or the egg may also carry particles (in 

 some cases even viruses) responsible for neoplastic developments 

 if suitable conditions permit the formation of cancer-determining 

 catalysts. 



There is reason to believe that the structures determining the 

 specificities of some biocatalysts are, in part at least, held together 

 by forces much weaker than those of primary chemical valency — 

 by van der Waals forces, adsorption, or hydrogen bonds. That 

 these forces are strengthened by desiccation and weakened by 

 hydration is well known to all users of aqueous adhesives. Em- 

 bryonic tissues are much more highly hydrated than adult tissue, 

 and this might be a factor in their susceptibility to catalyst change. 

 In the presence of suitable specific particles, new self-duplicating 

 catalyst areas might form and lead to cancer. The phenomenon 



