Contents XXV 



CHAPTER PAGE 



stances, 133: (a) Cytoplasm and karyoplasrfi differentiated 

 areas of a common basic substance, 135; (6) Details of cyto- 

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

 i a i-<- of protoplasm, 138; (d) "No universal formula for proto- 

 plasmic structure," 139. Preliminary remarks on the bearing 

 of physical chemistry on the protoplasm doctrine, 140. Ex- 

 perimcnfal erldence for the specificity of protoplasms, 143: 

 (a) Greater fusibility between closely related species as in 

 tissue mixtures and grafts. /f/; (b) Protoplasms and not 

 protoplasm must be the form of the protoplasmic conception, 

 148. 



VI. THE ORGANISM AND ITS CELLS ....... 150 



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



1 ''><>: (a) Importance and general character of the theory, 

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

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

 knowledge, 154. Certain lnde<nicles of the cell-theory, 158: 

 (a) As tested by embryonic dt>re!oiitent, 158; (b) As tested 

 by isolated cells and tissues, 167. 



VII. THE CELL-THEORY NOT SUFFICIENT FOR EXPLAINING THE OR- 



(1 AN ISM ........... 179 



More general inadc<inaci/ 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 mttaplaty of differen- 

 tiated cells, 186. Summary of examination, of inadequacy of 

 cell-theory, 190. Advance toward the orgaiiisnial standpoint 

 through conrcfi/ion of cell reached hi/ biochemistry pursued in 

 accordance trilh 1lte iirincifilefi of j^it/siciil chemintry, 191. 



VIII. FTRTHEH I-'XAM i NATION OF THE CELL-THEORY . . . 198 



The mosaic tin on/, //'X. What the mosaic theory is, 198; A 

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

 lolifiolence. .'<>_'. K.rperimental facts on irhich the theory 

 rests, 202. lialancini/ the account hefireen the mosaic and 

 totipotence theories, 206. The "i>romorphology" of germ cells, 

 211: (a) Facts of immediate ohscrralion on which the con- 

 ceji/ion rests, .'/.'; (l>) (, 'round* for believing minute observ- 

 able specific differences between germ cells important, 214! 



