APPLICATION TO METAZOA. 129 



SO opposed to facts which show a most intimate vital 

 relation between the body and the germ-cells, that 

 I think it would never have obtained credit were 

 it not a part of a theory which was developed with 

 great ingenuity, and which was partly based on the 

 profound truth of the continuity of the co-ordina- 

 tions of living matter. 



Professor Weismann has regarded the germ-cells 

 as parts upon which no molecular change could 

 be induced from without. All protoplasmic motion 

 is generally believed to be due to molecular changes, 

 and Professor Romanes has shown that in the undif- 

 ferentiated tissues of the jelly-fish, an irritation at 

 one part causes movement (molecular changes) to 

 be propagated -throughout the mass. We would 

 be unable to imagine the evolution of nerves, did 

 we not assume that all living matter possesses to 

 some degree the property of transmitting nervous 

 molecular changes ; and wherever vital communi- 

 cation exists between two parts, it must be possible 

 for molecular changes in one part to induce molec- 

 ular changes in the other. The evidence on this 

 point is somewhat obscured by the general presence 

 of special nervous courses, yet the evolution of nerve 

 courses compels us to the conclusion that their 

 properties exist in some degree in the undifferen- 

 tiated tissues, as in the case of the jelly-fish, where 



