HEREDITY 165 



to disappear when the spermatozoa enter the mucus 

 of the uterus. When we descend lower in the scale 

 of creation, in both sexuate and asexuate forms of 

 reproduction the dynamic element is always present. 

 We see it in the simple fission of such organisms as 

 the hydra and vorticella. We trace it again in the 

 segmentation of the ovulum of the aphides, in the 

 swimming zoospores of algse, in the antherozoids, in 

 the divisions of the cell fecundated by the favilla 

 of the pollen.* Look where we will there is ample 

 evidence that force plays a great and preponderating 

 part in reproduction. 



There is a rather prevalent belief that acquired The trans- 



'■ mission of 



characteristics cannot be transmitted from parent to acquired 

 offspring. If a man, it is said, lose a finger, or a istics. 

 hand, or an arm, his children will not on that account 

 show any such deficiency. Doubtless in such a case a 

 child might inherit its fingers, or hands, or arms, 

 from its mother and not from its father, or partly 

 from the one and partly from the other, the positive 

 influence of the former naturally outweighing the 

 negative influence of the latter. But even in the most 

 improbable event of both parents having lost the same 

 finger or hand, there is, according to the dynamic 

 theory of heredity, a possibility of their issue being 

 quite normal in this respect. Though the parts 

 might be wanting it does not necessarily follow that 

 the nerve centres on which they once depended have 

 undergone degeneration. A sensation of pain is often 

 * Letourneau, loc cit., pp. 316-318. 



