CHAPTER XXXV 



HEREDITARY PATRIMONIES IN FECUNDATION 



IN our eighth part we studied phenomena of heredity, sup- 

 posing the children to have a single parent, from which they 

 receive directly the hereditary patrimony. This is verified 

 in cases of parthenogenesis and also in reproduction by 

 spores (in the latter case, however, heredity is often masked, 

 at least morphologically, by the passage from the fern state 

 to the prothallus state). 



Things are otherwise in the most frequent cases. The 

 egg comes from the fusion of a spermatozoid and an ovule 

 taken from two different parents who consequently have 

 different hereditary patrimonies. Clearly, the idea we have 

 of the formation of the new hereditary patrimony in the act of 

 fecundation will depend on the idea we have first adopted 

 concerning the nature of sexual maturation and then of the 

 manner in which fecundation is effected in detail. Whatever 

 theory we adopt, there is one thing common to all, namely, 

 that what is common to father and mother is transmitted 

 integrally to the child in the act of fecundation. Discus- 

 sion arises only concerning characters which differ in the 

 progenitors. For example, two beings of the same species 

 and race always have children of the same species and race 

 as themselves. As to the characters which differ in father 

 and mother individual characters biological schools sus- 

 tain contradictory theses. 



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