162 THE OLDER HYBRIDISTS 
ticular flower, so that, if he had had any hint of the 
actual microscopic processes of fertilization, he would 
have been quite prepared for the more fundamental 
discovery. 
KGlreuter, indeed, believed that the act of fertiliza- 
tion consisted in the intimate mingling together of two 
fluids, the one contained in the pollen-grain, and the 
other secreted by the stigma of the plant. The mingled 
fluids, he supposed, next passed down the style into 
the ovary of the plant, and arriving at the unripe 
ovules, initiated in them those processes which led to 
the formation of seeds. In this belief Kélreuter simply 
followed the animal physiologists of his time, who 
looked upon the process of fertilization in animals as 
taking place by a similar mingling together of two 
fluids. Now that we know that fertilization consists 
essentially in the intimate union of the nuclei of two 
cells, one of which, in the case of plants, is the ovum 
contained within the ovule, whilst the other is repre- 
sented by one of a few cells into which the contents 
of the pollen-grain divide, we can understand more 
clearly the bearing of KGélreuter’s observation. And 
it is greatly to this eminent naturalist’s credit that he 
succeeded in carrying out his observations with so 
much accuracy, when the full meaning of those 
observations was of necessity hidden from his com- 
prehension. 
Kélreuter was the first to observe accurately the 
different ways in which pollen can be naturally con- 
veyed to the stigma of a flower. This may take place 
either by the pollen-grains falling directly upon the 
