June 23, 1916] 



SCIENCE 



877 



what takes place in crown gall, I think we 

 are warranted in searching for an intra- 

 cellular parasite, probably some common 

 organism, as the unknown factor, neces- 

 sary to satisfy the equation and explain 

 the phenomena. Moreover, I fail to see 

 how the assumption of a parasite makes the 

 explanation of tumor growth "more diffi- 

 cult." These objectors are here dealing 

 with one of their many assumptions while 

 I am dealing with a fact. I insert my in- 

 fected needle and I obtain a tumor. I in- 

 sert a sterile needle and the wound heals 

 normally. Into one branch of a young 

 Paris daisy I set my infected needle 50 

 times and obtained 50 tumors; at the same 

 time into the twin branch I set a sterile 

 needle 50 times and obtained no tumors 

 whatsoever, but only a normal healing of 

 the wounds. Cell proliferation per se in 

 no way explains cancer. Normal cells, also, 

 judging from the way they behave in blood 

 serum under the microscope, must often 

 proliferate into the plasma of the body, but 

 such wandering cells are promptly dis- 

 posed of in accordance with the law of 

 antagonism or of physiological control, or 

 whatever you please to call it. I mean the 

 action of the body as a whole. Otherwise, 

 we should have occurring continually in 

 the body what takes place when normal 

 tissues are cultivated in vitro, that is, a 

 copious cell proliferation, which would be 

 disastrous. This we do have in cancer, but 

 since cancer develops in opposition to all 

 the compelling forces of the animal body it 

 must be owing to a profound disturbance of 

 the normal (interior) activities of the cells 

 involved. What is so likely as a micro- 

 organism to produce this cell disturbance 

 leading to the formation of a tumor ? Espe- 

 cially what, since in the plant we know 

 that one does produce just that? 



10. Cancers are due to long-continued 

 inflammatory conditions. They begin in 



bruises, in old (unhealed) wounds, X-ray 

 burns, charcoal stove burns (Kangri can- 

 cer), and various irritations and injuries 

 incident to special trades (chimney sweeps' 

 cancer, paraffin workers' cancer, etc.). 

 Answer: The second statement is admitted. 

 They begin in all of these places. The first 

 statement is a non sequitur, a post hoc ergo 

 propter hoc argument. Wounds are often 

 infected with visible parasites, why not 

 sometimes with invisible ones ? Not all irri- 

 tations end in cancers. Of two long-con- 

 tinued irritations one may become malig- 

 nant and the other not. This is wholly in- 

 explicable on the theory of simple irrita- 

 tion, but readily interpreted if we assume 

 that cancer is due to a special and unusual 

 kind of parasite, certain long-continued 

 irritations having paved the way for a 

 peculiar infection by having reduced the 

 resistance of the body. 



11. Surgeons, nurses and relatives do not 

 contract cancer. It therefore does not be- 

 have like a communicable disease. Answer: 

 Neither does malarial fever; neither does 

 arthritis ; neither does leprosy ; and, finally, 

 neither does crown gall. We must recognize 

 that in nature there are all grades of para- 

 sitism and must be prepared to welcome 

 forms not hitherto recognized. In pathol- 

 ogy, as everywhere else, the open mind is 

 after all the best asset. Closed and crystal- 

 lized minds are of no further use in the 

 world ! Certainly cancer is not an acute in- 

 fection, and no one regards it as such. It 

 may be due, however, to a parasite, visible 

 or invisible as the case may be, some feeile 

 parasite against which the normal hody is 

 fully protected, some common organism, 

 living saprophytically on the body, or in 

 the soil, able only to infect a depleted body, 

 and destructive only when through wounds 

 (very slight ones, it may be) it has pene- 

 trated into the interior of certain cells, 

 which neither kill it nor are killed by it, but 



