374 Menders Experiments 



assimilation and formation of new cells to become an in- 

 dependent organism. This development follows a constant 

 law, which is founded on the material composition and 

 arrangement of the elements which meet in the cell in a 

 vivifying union. If the reproductive cells be of the same 

 kind and agree with the foundation cell [fertilised ovum] of 

 the mother plant, then the development of the new indi- 

 vidual will follow the same law which rules the mother 

 plant. If it chance that an ^gg cell unites with a dissimilar 

 pollen cell, we must then assume that between those 

 elements of both cells, which determine opposite characters 

 some sort of compromise is effected. The resulting 

 compound cell becomes the foundation of the hybrid 

 organism, the development of which necessarily follows 

 a different scheme from that obtaining in each of the two 

 original species. If the compromise be taken to be a 

 complete one, in the sense, namely, that the hybrid embryo 

 is formed from two similar cells, in which the differences 

 are entirely and permanently accommodated together, the 

 further result follows that the hybrids, like any other stable 

 plant species, reproduce themselves truly in their offspring. 

 The reproductive cells which are formed in their seed 

 vessels and anthers are of one kind, and agree with the 

 fundamental compound cell [fertilised ovum]. 



With regard to those hybrids whose progeny is variable 

 we may perhaps assume that between the differentiating 

 elements of the ^gg and pollen cells there also occurs a 

 compromise, in so far that the formation of a cell as 

 foundation of the hybrid becomes possible ; but, never- 

 theless, the arrangement between the conflicting elements 

 is only temporary and does not endure throughout the life 

 of the hybrid plant. Since in the habit of the plant no 

 changes are perceptible during the whole period of vege- 

 tation, we must further assume that it is only possible for 

 the differentiating elements to liberate themselves from the 

 enforced union when the fertilising cells are developed. In 

 the formation of these cells all existing elements participate 



evident proof of the complete union of the contents of both cells is afforded 

 by the experience gained on all sides that it is immaterial, as regards the 

 form of the hybrid, which of the original species is the seed parent or 

 which the pollen parent. 



