690 APPENDIX B. 



existence, individuals of the European races who were less capable 

 than others of crouching and squatting, gained by those minute 

 changes of structure which incapacitated them, such advantages 

 that their stirps prevailed over other stirps an absurd suppo 

 sition. 



And now I must once more point out that a grave responsi 

 bility rests on biologists in respect of the general question ; since 

 wrong answers lead, among other effects, to wrong beliefs about 

 social affairs and to disastrous social actions. In me this convic 

 tion has unceasingly strengthened. Though The Origin of Species 

 proved to me that the transmission of acquired characters cannot 

 be the sole factor in organic evolution, as I had assumed in So 

 cial Statics and in The Principles of Biology, published in pre- 

 Darwinian days, yet I have never wavered in the belief that it is 

 a factor and an all-important factor. And 1 have felt more and 

 more that since all the higher sciences are dependent on the 

 science of life, and must have their conclusions vitiated if a fun 

 damental datum given to them by the teachers of this science is 

 erroneous, it behoves these teachers not to let an erroneous datum 

 pass current : they are called on to settle this vexed question one 

 way or other. The times give proof. The work of Mr. Benjamin 

 Kidd on Social Evolution, which has been so much lauded, takes 

 Weismannism as one of its data ; and if Weismannism be untrue, 

 the conclusions Mr. Kidd draws must be in large measure erro 

 neous and may prove mischievous. 



POSTSCRIPT. Since the foregoing pages have been put in type 

 there has appeared in Natural Science for September, an abstract 

 of certain parts of a pamphlet by Professor Oscar Hertwig, set 

 ting forth facts directly bearing on Professor Weismann s doctrine 

 respecting the distinction between reproductive cells and somatic 

 cells. In The Principles of Biology, 77, I contended that repro 

 ductive cells differ from other cells composing the organism, only 

 in being unspecialized. And in support of the hypothesis that 

 tissue-cells in general have a reproductive potentiality, I instanced 

 the cases of the Begonia, phyllomaniaca and Malaxis paludosa. In 

 the thirty years which have since elapsed, many facts of like sig 

 nificance have been brought to light, and various of these are 

 given by Professor Hertwig. Here are some of them : 



&quot; Galls are produced under the stimulus of the insect almost anywhere 

 on the surface of a plant. Yet in most cases these galls, in a sense grown 

 at random on the surface of a plant, when placed in damp earth will give 

 rise to a young plant. In the hydroid Tubularia mescmbri/anthcmum, when 

 the polyp-heads are cut off, new heads arise. But if both head and root be 

 cut off, and the upper end be inserted in the mud, then from the original 

 upner end not head-polyps but root filaments will arise, while from the 

 original lower end iiot root filaments but head-polyps will grow. . . . 



