June 23, 1916] 



SCIENCE 



887 



neeted with the primary tumor by a tamor- 

 strand which is lodged in the outer cortex 

 and is vascular, i. e., has the structure of a 

 diminutive stem (stele). 



What is still more astonishing, I find 

 that I can produce these teratomas in the 

 leaves of tobacco plants, where no dormant 

 buds are known to exist.^ To get these re- 

 sults the leaves must be fairly young, i. e., 

 plastic. They will then produce tumors 

 where they are inoculated (needle-pricked) 

 and many of these tumors will be covered 

 with leafy shoots (tobacco plants in minia- 

 ture). I have obtained seven such tera- 

 tomas from the blade of a single leaf, and 

 twenty-seven from the leaves of a single 

 plant — ^too many to be due to Cohnheim's 

 "cell-rests." They must have originated, 

 I think, from groups of plastic (totipotent) 

 cells normal to the inoculated parts of the 

 leaves and probably also present in many 

 uninoculated parts of such leaves, if not in 

 all parts. 



How, then, can these phenomena be ex- 

 plained? The teratoids I have obtained 

 being essentially like the embryonal tera- 

 tomas in animals, I believe that in both 

 plants and animals they must have the 

 same origin, i. e., must arise from an iden- 

 tical chemical and physical stimulus. So 

 far I have been able to explain the em- 

 bryonal teratomas only on the assumption 

 that in all animals and in all plants (except 

 the simplest) certain widely distributed 

 normally arranged cells or groups of cells, 

 possibly all cells when very young and 

 plastic carry the potentiality of the whole 

 organism, which potentiality is not ordi- 

 narily developed on account of division of 

 labor, but which comes into action when 

 hindrances are removed, i. e., when the 

 physiological control is disturbed or de- 

 stroyed. "We know that life must have 



8 See Journal of Agric. Besearch, April 24, 1916, 

 Plate XXIII. 



begun so in unicellular plants and animals 

 and there is no good reason why it should 

 not have continued so in multicellular ones. 

 Only we have not been accustomed to think 

 of it in this way, yet there are many facts 

 respecting regeneration of lost parts in 

 both plants and animals which coincide per- 

 fectly with this view. Coinciding with this 

 view as to the origin of embryomas in vari- 

 ous organs, i. e., from groups of normal but 

 very young undifferentiated or but slightly 

 differentiated cells or groups of cells multi- 

 plying under a cancer stimulus, is the fact 

 that I have been able to produce the tera- 

 tomas in tobacco leaves only by inoculating 

 very young leaves. When older leaves are 

 inoculated they either do not respond or 

 yield only the ordinary crown galls. 



I may be permitted a few general re- 

 marks in conclusion, premising that this is 

 the way the cancer problem looks to an ex- 

 perimental biologist. 



With some praiseworthy exceptions, the 

 cancer specialists of to-day, following the 

 lead of the Germans, and their English 

 imitators, are lost in a swamp of morphol- 

 ogy, and it is time that an entirely new set 

 of ideas should be promulgated to rescue 

 them from their self-confessed hopelessness. 



When a pathologist can say: "Concern- 

 ing the ultimate nature of neoplastic over- 

 growth we shall never have more than a 

 descriptive knowledge," he has reached the 

 end of the road in his direction and the 

 limit of pessimism ! I do not care a rap 

 whether I am called orthodox or heterodox, 

 but I do care tremendously to keep an open 

 mind and a hopeful spirit. One trouble 

 with too many cancer specialists is that 

 they are not biologists, whereas the cancer 

 problem is peculiarly and preeminently a 

 biological problem. These cancer morphol- 

 ogists have patiently cut and stained and 

 studied hundreds of thousands of sections 

 of tumors, fining and refining their defini- 



