Packard.] INSECTS OF THE PLANT HOUSE. 
109 
or a Humboldt ? Simple as the process appears to our eyes, 
the determining cause is still an unfathomed mystery. The 
humble truth-seeking observer can only ponder and work on, 
hoping that the solution may be possible to his race. Cer¬ 
tainly all is not known, when with some naturalists and phi¬ 
losophers we attempt to settle the question by saying that life 
is a function of protoplasm ; though it is granted that life on 
this globe does not exist without it. For protoplasm is po¬ 
tentially a very variable substance, and life a problem quite 
beyond the science of our day to settle, whatever may be the 
flood of light thrown upon the question by modern science. 
The life force existing in protoplasm is powerless without an 
Infinite intelligence and will urging it on in its destined 
channels, just as muscular force is subject to the finite will 
that calls it forth. Though muscular force is a function of 
muscle, that does not account for a muscular act, nor does 
the. nerve cell or fibre account for a nervous act; both are 
impelled by a will force not of themselves, as Matthew Arnold 
would sa}\ So at the outset all life may have been the re¬ 
sult of chemico-pliysical forces, producing from its elements, 
and acting upon the compound thus produced, which we call 
protoplasm. Still this act of “spontaneous” generation was 
none the less under the guidance of an all-pervading intelli¬ 
gence and will. Spontaneous generation is not self-creation. 
So the study of our little Aphides ends in starting a series 
of questions that haunt us each step we take, some of them 
the largest that baffle the human reason. Certainty the mind 
of the naturalist need not grow rusty. Problems of matter 
and life and spirit assail him on every side, and the calm¬ 
ness, patience and breadth of conception their consideration 
involves are a fitting preparation for encountering the prob¬ 
lems of his own existence. 
Our studies over, now arises a practical question. How 
shall w r e exterminate these troublesome pests? In dealing 
with these insects in the hot house, where there are no insect 
13 
