148 The Unity of the Organism 



former individuality still supplies to the others certain es- 

 sential food substances from its own body and activities es- 

 sential to the other. The relation between the two organ- 

 isms which are grafted together seems similar in important 

 respects to the relation between two organisms living to- 

 gether symbiotically. In fact, a graft combination might 

 be spoken of as an artificial symbiosis. On the whole, then, 

 the morphologico-physiological study of the ability of or- 

 ganisms to fuse together bodily points unmistakably to the 

 belief that different kinds of organisms must contain in their 

 make-up certain fundamental substances that are different 

 as well as certain others that are very much alike if not 

 quite identical. In other words such studies furnish no 

 warrant for the conception of a physical basis of life identi- 

 cal in all living beings. 



{h) Protoplasms, Not Protoplasm, Must Be the Form of the 



Protoplasmic Conception 



Studies of this kind show that if the term protoplasm is 

 to have any scientific usefulness it must be used in the plural 

 — protoplasms — and so must be subject to the practices 

 and principles of biological description and classification in 

 the same way that all other biological entities are, and the 

 great and ever-increasing munber of elements now known 

 with more or less definiteness as entering into the makeup 

 of living substance must, I believe, be looked at in this light 

 by all departments of biology as w^ell as by natural history. 

 Protoplasms are the substances of which individual or- 

 ganisms are composed, so the protoplasms as well as the 

 organisms must be individuated. 



To set forth the facts and reasonings upon which such a 

 conception of protoplasm must rest is one of the foremost 

 objects of several of the discussions in this treatise. Those 

 on the organism and its chemistry, and the organism and its 

 cells, are especially dedicated to this end. 



