Bisexual Crosses 287 



result, having the new attribute in addition to 

 all the variability of the old types. In scientific 

 experiments made for the purpose of investi- 

 gating the general laws of hybridity, such com- 

 plex cases are therefore to be wholly excluded. 

 The hereditary purity of the parents must be 

 considered as one of the first conditions of 

 success. 



Moreover the progeny must be numerous, 

 since neither constancy, nor the exact propor- 

 tions in the case of instability, can be deter- 

 mined with a small lot of plants. 



Finally, and in order to come to a definite 

 choice of research material, we should keep in 

 mind that the chief object is to ascertain the 

 relation of the offspring to their parents. Now 

 in nearly all cases the seeds are separated from 

 the fruits and from one another, before it be- 

 comes possible to judge of their qualities. One 

 may open a fruit and count the seeds, but ordi- 

 narily nothing is noted as to their characters. 

 In this respect no other plant equals the corn 

 or maize, as the kernels remain together on the 

 spike, and as it has more than one variety 

 characterized by the color, or constitution, or 

 other qualities of the grains. A corn grain, 

 however, is not a seed, but a fruit containing a 

 seed. Hence the outer parts pertain to the par- 

 ent plant, and only the innermost ones to the 



