314 College of Forestry 
factory understanding of any part. If one wishes to become 
acquainted with the black bass, for example, he will learn 
but little if he limits himself to that species. He must evi- 
dently study also the species upon which it depends for its 
existence, and the various conditions upon which these 
depend. He must likewise study the species with which it 
comes in competition, and the entire system of conditions 
affecting their prosperity. Leaving out any of these, he is 
like one who undertakes to make out the construction’ of a 
watch, but overlooks one wheel; and by the time he has 
studied all these sufficiently, he will find that he has run 
through the whole complicated mechanism of the aquatic 
life of the locality, both animal and vegetable, of which his 
species forms but a single element.” 
“In such a general survey of the plants and animals of a 
region, the study of their food relations will be found to 
afford an admirable objective point. Doubtless, of all the 
features of the environment of an individual, none affect it 
at the same time so powerfully, so variously and so inti- 
mately as the elements of its food. ‘ Even climate, season, 
soil, and the inorganic circumstances generally, influence an 
animal through its food quite as much as by their direct 
action. It is through the food relation that animals touch 
each other and the surrounding world at the greatest number 
of points, here they crowd upon each other the most closely, 
at this point the struggle for existence becames sharpest and 
most deadly; and, finally, it is through the food relation 
almost entirely that animals are brought in contact with the 
material interests of man. Both for the student of science 
and for the economist, therefore, we find this subject of 
peculiar interest and value. It includes many of the most 
important relations of a species, and may properly be made 
the nucleus about which all the facts of its natural history 
are gathered.” 
If the statement of Forbes be true, and all who have 
studied the subject even slightly will assuredly agree that it 
is, then there is a large amount of work still to be done 
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