64 MISSOURI BOTANICAL GARDEN. 
less plants with the defense which the hellebore has learned 
to manufacture as a meansof defense against these enemies 
of its own foliage? 
There is another application of the same idea which is 
illustrated by the very latest work of our entomological 
laboratories. As there is a class of insects which, as we 
all know, live entirely upon living vegetation, the botanists 
now say that there is a class of plants which, on the other 
hand, live entirely upon living insects. The plant world 
has, in short, learned to retort upon the insect world. And 
we are learning to use these natural enemies, these plant 
enemies of insects, for the defense of other plants. We 
have learned lately for example, that one of the most deadly 
and destructive of these may be readily cultivated in great 
quantities in as simple a thing as corn meal mush, if you 
only make your mush with soup instead of with water. How 
easy a thing it would be for a horticulturist to maintain a 
crop of these deadly agents, so that their spores might float 
everywhere and settle upon any insect that would be apt to 
injure the vegetation! These are all evidences of the fact, 
which is illustrated more amply than I shall be able to 
illustrate it to-night, that the greatest success in attempts 
to accomplish our purposes with respect to natural objects 
is to be attained by utilizing the methods and the system 
and the expedients of nature, and by a more general and a 
wider application of those methods. 
Before I take my seat I desire to express, as an ento- 
mologist, my interest in what Henry Shaw has done, and 
in what those who are carrying out his will are doing here: 
not in behalf of entomology alone, but of horticulture and 
agriculture, because these sciences are so related to each 
other that whatever improves, advances, or encourages 
one, improves, advances and encourages the other also. 
Entomology is in some senses a subordinate science. Ina 
practical way, it shines partly by its own light and partly 
by a reflected light; and you may be sure that we are much 
interested in the sources from which this light comes, 
