Contents xxv 



CHAPTER PAGE 



stances, 133: (a) Cytoj)lasr)i and karyoplasm differentiated 

 areas of a common ba^sic substance, 135; (b) Details of cyto- 

 plasmic structure, 137; (c) Three main theories of the struc- 

 ture of protoplasm, 138; (d) "No universal formula for proto- 

 plasmic structure," 139. Preliminary remarks on the bearing 

 of physical chemistry on the protoplasm doctrine, I40. Ex- 

 perimental evidence for the specificity of protoplasms, 1^3: 

 (a) Greater fusibility between closely related species as in 

 tissue mixtures and grafts, 1^3; (b) Protoplasms and not 

 protoplasm must be the form of the protoplasmic conception, 

 148. 



VI. The Organism and its Cet.t.s 150 



What the cell-theory is, viewed historically and substantively, 

 150: (a) Importance and general character of the theory, 

 150; (b) Various forms of the theory as currently held, 150; 

 (c) Statement of the theory justified by present state of 

 knowledge, 154- Certain inadequacies of the cell-theory, 158: 

 (a) As tested by embryonic development, 158; (6) As tested 

 by isolated cells and tissues, 167. 



179 



VII. The Cell-theory not Sufficient for Explaining the Or- 



ganism .....>..... 



More general inadequacy of the cell-theory, 179: (a) As 

 tested by the regeneration and restitution of mutilated organ- 

 isms, 179; (b) As tested by the principle of aggregation, 182. 

 (c) As tested by the specificity and metaplasy of diferen^ 

 tiated cells, 186. 8umm,ary of examiiuition of inadequacy of 

 cell-theoinf , 190. Advance toward the organi-smal standpoint 

 through conception of cell reached by biochem^istry pursued in 

 accordance with the principles of physical chemistry , 191. 



VIII. Further Examination of the Cell-Theory . . . 198 

 The mosaic theory, 198. What the mosaic theory is, 198; A 

 modicum of truth in the mosaic theory, 198. The theory of 

 tofipotence, 202. Experimental facts on which the theory 

 rests, 202. Balancing the accotint between the mosaic and 

 totipotence theories, 206. The "promorphology" of germ cells, 

 211: {a) Facts of i/tnmediate observation on which the conr- 

 ception rests, 212; (6) Grounds for believing minute observ- 

 able specific differences betiveen germ> cells important, 214; 



