1892.] The Difficulties in the Heredity Theory. 563 
The Nature of the Relation Between the Body-cells 
and Germ-cells.—I have already shown that we are forced to 
infer that such a relation exists by the facts of evolution, 
although these facts show that the transmission of normal ten- 
dencies from the body to the germ-cells is ordinarily 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 pathological is not diseased, and inheritance of a 
variation is not from the influence upon one individual neces- 
sarily, but upon a row of individuals. This isin the normal 
condition of things. In the abnormal condition the rate of 
transmission may be accelerated. 
Does this transmission depend upon an interchange of mate- 
rial particles or upon an interchange of forces, or both? 
There are three phenomena about which there is much scep- 
ticism, to say the least, which bear upon the question of a pos- 
sible interchange of forces between the body and germ-cells. 
These are the inheritance of mutilations, the influence of pre- 
vious fertilization, and the influence of maternal impressions. 
They are all in the quasi-scientific realm, which embraces 
such mental phenomena as telepathy. That is, we incline to 
deny them simply because we cannot explain them. 
Mutilations—Since the publication of Weismann’s essays 
the subject of inherited mutilations has attracted renewed 
interest. I would first call attention to the fact that this mat- 
ter has only an indirect bearing, for a mutilation is something 
impressed upon the organism from without; it is not truly 
“ acquired ;” the loss of a part by accident produces a sudden 
but a less profound internal modification of the organism than 
the loss of a part by degeneration. Most of the results are 
negative; many of the so-called “certain” cases prove upon 
investigation to be mere coincidences. Weismann? himself 
experimented upon white mice, and showed that nine hun- 
dred and one young were produced by five generations of arti- 
1Ueber den Transformismus, Archiv f. Anthropologie, 1888, p. 1. 
*Biological Memoirs, p. 432. 
