PRESENT PROBLEMS IN EVOLUTION AND HEREDITY. 351 



I ]i;ive merely touched upon tliese speculations to sliow that the un- 

 known factors in heredity are also the unknown factors in operation in 

 living matter. All we can study is the external form, and conjecture 

 that this form represents matter arranj>ed in a certain way l>y forces 

 ])eculiar to the orijanism. Tliese forces are exhibite<l or ])atent in the 

 somatic cells; they are ])otential or latent in the germ cells. 



The last stage of our inquiry is as to the mode in which the action of 

 habit or environment ui)oii the somatic cells can be brought to l)ear 

 upon the germ cells. 



The nature of tJn' relation l)eticeen the body eell.s and (jerm eells. — I 

 hav(! already shown that we are forced to infer that such a. relation 

 <'xists by the facts of evolution, although these facts show that the 

 transmission of normal tendencies from the body to the germ cells is 

 ordiiuirily an extremely slow process. 



Virchow* says every variation in race character is to be traced back 

 to the pathological condition of the originator. All that is pathologi- 

 cal is not diseased, and inheritance of a variation is not from the intlu- 

 enc*' u])on one indi^ idual necessarily, but upon a row of individuals. 

 This is in the nornuil condition of things. In the abnormal condition 

 the rate of transmissiou may be accelerated. 



Does this transmission depeiul u])on an interchange of material par- 

 ticles, or upon an interchange of forces, or both? 



There are three phenomena about which there is nuu-h skepticism, to 

 say the least, which bear npon the question of a possible interchange 

 of forces between the body and the germ cells. These are the inherit- 

 ance of mutilations, the influence of previous fertilization, and the in- 

 fluence of maternal impressions. They are all in the quasi-scientitic 

 realm, which embraces such mental plienomenaas telej)atliy. That is, 

 we incline to deny them siin])l> because we can not explain them. 



Mutilati(»ns. — Siiu-e the ]»ub]ication of Weisniann's essays the sub- 

 ject of inherited mutilations has attracted renewed interest. I would 

 flrst call att<'ntion to the fact that this matter has only an indiicct bear- 

 ing, foi- a mutilation is something impressed U])on the organism from 

 without; it is not truly "ac<iuired;" tlie loss of a {)art by accident i)ro- 

 duces a sudden but a less profound internal modilication of the organism 

 than the loss of a i)art by degeneration. Most of the results are nega- 

 tive; many of the so-called ''certain" cases i)rove upon investigation 

 to be niere coincidences. Weismannf himself experimented upon white 

 jnic(% and showed that 1M)1 young were produc^ed by five generations of 

 artilicially mutilated parents, and yet there was not a single example of 

 a rudimentary tail or of any other abnormality in this organ. The cases 

 of cleft ear lobule have recently been summed u]).j Israel reports two 

 cases of clefts in wlii(;h the parent's ears were normal. Schmidt and 



* "Uel)er den Transfonnismus,'' Archivf. Anthropologic, IHH^, ]>. 1. 



t liidlof/icdl ^f(■m(nrl^, 2>.432. 



\ Jourtml <if .liKihiuni iiii'l rin/xiolnfii/, \W\, ]). I'A'A. 



