KNIGHT 167 
that Mendel’s law was afterwards discovered. This 
very discovery might even have been made by Knight 
himself, if he had only realized the importance of ascer- 
taining on a large scale the numerical proportions in 
which the different kinds of plants, arising in the 
second generation from the crosses, made their appear- 
ance. Unfortunately, this particular form of inquiry 
never seems to have occurred to him. 
Knight’s experiments were made with a different 
object in view—namely, that of discovering whether 
a cross with a distinct race would provide the stimulus 
necessary to restore its lost vigour to a strain of plants 
which was supposed to have become debilitated, owing 
to its members having been bred exclusively by self- 
pollination for a long series of generations. 
The result of the experiments undoubtedly estab- 
lished the fact that in some cases the hybrid offspring 
of two distinct races shows a more vigorous habit of 
growth than either of the parental types. The follow- 
ing extract from Knight’s own account will indicate 
the nature of the experiments upon which his con- 
clusions rest : . 
‘ By introducing the farina of the largest and most 
luxuriant kinds into the blossoms of the most diminu- 
tive, and by reversing this process, I found that the 
powers of the male and female, in their effects on the 
offspring, are exactly equal. The vigour of the growth, 
the size of the seeds produced, and the season of 
maturity, were the same though the one was a very 
early, the other a very late variety. I had in this 
experiment a striking instance of the stimulative effects 
