June 23, 1916] 



SCIENCE 



875 



cause of cancer, the interpretation of the 

 results would be entirely wrong, i. e., they 

 would be ascribed wholly to heredity, 

 whereas we know that two factors are in- 

 volved: (1) heredity; (2) infection. I do 

 not think Miss Slye has established the fact 

 that cancer follows Mendel's law. 



4. There is no need to postulate any para- 

 site, since the cancer cell itself is the all- 

 sufficient parasite and no cancers can be 

 produced in the absence of this cell. An- 

 siver: It is strange that the authors of this 

 statement, which has been dinned into us 

 for a generation, can not see that it is no 

 answer at all, but only a makeshift. As 

 well say: Tetanus is due to tetanin. Cer- 

 tainly, we all admit this, but what orig- 

 inates the tetanin? and what originates the 

 cancer cell? Moreover, loath as these ob- 

 jectors are to admit it, cancers (sarcomas) 

 in barnyard fowls can now be induced by 

 cancerous material all the cells of which 

 have been removed by filtration, or have 

 been killed by heat, by freezing, ov by dry- 

 ing (Rous). And how should anemias and 

 cachexias arise as the simple result of the 

 proliferation of body cells? In other dis- 

 eases they are the direct result of bacterial 

 or protozoan multiplication in the body. 

 In this connection reflect for a moment on 

 what goes on in streptococcal arthritis, in 

 persistent agues, or in yellow fever and in 

 blackwater fever where the red blood cor- 

 puscles are destroyed wholesale. Even per- 

 nicious anemia will, I believe, be traced 

 eventually to a blood-destroying parasite. 

 All that we yet know definitely concerning 

 the natural occurrence of anemias (I am 

 purposely excluding surgical ones) is that 

 in certain diseases they are due to blood- 

 destroying parasites, and it is not going 

 very far afield to assume that anemia is 

 so produced in cancer. 



5. The idea of a parasite is too complex. 

 "We know that we can graft cancer only 



within the narrowest limits, and also that 

 within the same species each sort of cancer 

 reproduces its own kind. We must there- 

 fore postulate not only as many different 

 cancer parasites as there are animals sub- 

 ject to cancer, and that is probably every 

 kind of animal, but also a parasite for every 

 special kind of cancer in each particular 

 animal, which is a reductio ad absurdum. 

 Answer: This is a molehill magnified into a 

 mountain — an unsubstantiated and unwar- 

 ranted hypothesis! The history of science 

 is full of such objections. Against the 

 plainest evidence it is always easy for cer- 

 tain types of mind to raise objections, which 

 then generally are left to some one else 

 laboriously to test out experimentally, 

 whereupon they vanish into thin air, the 

 objections not having been well grounded. 

 Some people are good only as objectors! 

 They can not do anything concrete. It is 

 less than twenty years since certain theoret- 

 ical Germans were saying: There are no 

 bacterial diseases of plants and can not be 

 any, for the reasons we have given. Yet 

 the experimental method has demonstrated 

 the existence of nearly a hundred. In sci- 

 ence, no theory is worth a picayune that 

 does not have an experimental basis under 

 it! There have been at least thirty so- 

 called explanations of cancer origin pro- 

 pounded during the last half century, not 

 one of which really explains or has any 

 experimental basis under it. Cohnheim's 

 theory is one of these; Ribbert's is another. 

 From the behavior of the cells of one 

 species when grafted on another species we 

 can postulate nothing as to what a naked 

 microorganism would do under the same 

 circumstances. As a matter of fact, plants 

 also can not be grafted widely, yet the 

 crown-gall organism is widely inoculable. 

 Moreover, it yields one result tvhen inocu- 

 lated into one set of tissues and a different 

 result when inoculated into another set of 



