Acquired Characters and Congenital Variation

Abstract

PROBABLY many readers of the recent discussion on the transmission of acquired characters will regret that a more definite conclusion has not been arrived at. This is probably due to the fact that the premises now in our possession do not admit of a definite answer yet being given. Those who assume that there is no evidence in favour of the transmission of acquired characters are mostly, I presume, supporters of “the continuity of the germ-plasm” theory of Weismann. Almost everyone admits that individuals may and do acquire certain characters due to change in environment, use, disuse, &c.; but while many maintain that these characters are transmitted to offspring, others deny that such is the case, or think that the evidence is insufficient. In supporting “the continuity of the germ-plasm” theory it is impossible to suppose that the germ-plasm is continued from one generation to another like a portion of entailed property. For each individual gives off thousands of ova or spermatozoa as the case may be, only a very few of which go to produce new individuals; therefore there is a dissipation of “germ-plasm,”—that is to say, in the germinal cells of mammals of to-day there cannot be any of the identical “germ-plasm” which existed in their remote invertebrate ancestors ages ago. For all this dissipation there must be some constructive process, otherwise the germ-plasm would come to an end.