174 APPENDIX. 



biologists by the delightful pen of Weismann. The 

 " continuity of the germ plasm," the title by which 

 this view is generally known, expresses the fact that 

 germ substance continues in an unbroken line from 

 generation to generation ; a man is similar to his 

 parents because he develops out of a similar plasm. 

 The continuity of germ plasm (stirp of Galton), like 

 Darwin's selection, is a fact, not a theory. 



Now while Darwin's fancy regarding pangenesis 

 compels one to believe that the effects of use and 

 disuse, the action of disease and mutilation, must be 

 transmitted, the continuity of the germ plasm in the 

 isolated reproductive cells of the parents renders this 

 extremely doubtful. The anatomical conditions 

 actually found are fully reconcilable with the ob- 

 served non-transmission of acquired characters. 



This fact was shortly and precisely stated by 

 Galton in 1875, and by Weismann in his " Studies in 

 the Theory of Descent," published in English in 1882. 

 In 1883, in his essay upon Life and Death, 1 Weis- 

 mann looked upon the germ plasm as the substance 

 of the germinal or reproductive cells, and on p. 148 

 he defines " germ " as follows : " I should propose to 

 include under this term every cell, cytode, or group 

 of cells which, while not possessing the structure of 

 the mature individual of the species, possess the 

 power of developing into it under certain circum- 

 stances." So far Weismann was a fact man, and 

 gave to the facts observed their true and full signifi- 

 cance. Since that time, however, he has speculated 



1 Essay to be found in vol. i. ; English translation, 1889. 



