FURTHr.R RtSHARCHES IN DlSI-ASHS OF Pl.ANTS "S? 1 



Dr. E. J. Butler li.is written tlic lust account of our work on Crown Gall 

 that I have seen. He has i;ot in it all my notions about its relations to 

 Cancer and has made no mistakes. It forms the first part of a paper he 

 read on relation of botanical research to human diseases before an linglish 

 organization devoted to Tropical Medicine. 



The location of the parasite was significant, Smith believed, 

 from the standpoint of cancer research. The analogy between 

 crown gall and animal cancer was admittedly not complete. But 

 his persistent experiments to demonstrate bacteria within the cells 

 had extended over many years and were planned as studies in 

 cellular pathology^ The first paragraph of his conclusions as to 

 " Twentieth Century Advances in Cancer Research " ''■• began: 



What goes on inside a cancer cell that does not go on inside a normal 

 cell? If we knew that we should be very near the solution of the cancer 

 problem, and it is not beyond hope that eventually wc shall know just 

 that — chemically and structurally. We must conclude that the cell or its 

 progenitors has been under a foreign stimulus of some sort. Everything 

 we know about cancer points to this conclusion. In case of the crown-gall 

 bacteria, acid and alkaline by-products arc given off in siniple culture media 

 and we have a right to assume that they are also given oft inside the plant 

 where similar proteids and sugars are at their disposal. When applied to the 

 surface of the plant these substances set up chemical and physical changes 

 which lead to an excessive, disordered, hyperplasial growth and they 

 probably do this in the tissues where they are produced by the parasite, but 

 here our knowledge ends. 



This was so for crown gall. But, alike for tumors in animals 

 and perhaps in man, physical and chemical activities from many 

 causes — parasites among them — were known to bring about the 

 "cell-multiplication passing beyond physiological control " which 

 was one of the phrases used by Smith to explain cancer. Later 

 he spoke of " multiplying extraneous organisms " as activating 

 the origin of malignant tumors. 



Since Dr. Smith's years of research, in cancer laboratories of the 

 world, the transformation of normal mammalian cells into cancer 

 cells has been observed in vitro. A vast amount of environmental 

 and genetic learning about cancer induction has been accumulated. 

 Knowledge of the modes of cancer transmission is superior, 

 especially in the direction of cytoplasmic inheritance and trans- 

 placental transmission. Indeed, the knowledge of chemically in- 



"* op. cit., 315. 



