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and what is true of them is, I believe, true of all alliances of organisms. 
The first and most important is structural and generic: it is absolutely 
essential and is preserved in its perfection by the elimination, through 
natural selection, of all forms departing from it. The second is merely 
coincident, not essential, but nevertheless along lines that are of sec- 
ondary advantage. The third is purely fortuitous, affects superficial 
features in the main, is unessential (a consequence of the inherent ten- 
dency of all things to vary), and takes place along all lines and in all 
directions where there is no counteracting resistance. 
TRANSMISSION OF CHARACTERS THROUGH HEREDITY. 
Now, when it comes to the bearing which the history of these little 
moths has upon some of the larger questions that are now concerning 
naturalists (for instance, the transmission of acquired characters, orthe 
origin, development, and nature of the intelligence displayed by the 
lower animals), broad fields of interesting opinion and conclusion open 
up before us—fields that can not possibly be explored without trenching 
too much upon your time. I will close, therefore, with a few summary 
expressions of individual opinion, without attempting to elaborate the 
reasons in detail, and with the object of eliciting further discussion, 
which is oneotthe objects ofthis paper. My first conviction is that in- 
sect life and development give no countenance to the Weissmann school, 
which denies the transmission of functionally acquired characters, but 
that, on the contrary, they furnish the strongest refutation of the views 
urged by Weissmannand hisfollowers. The little moths of which I have 
been speaking, and indeed the great majority of insects, all, in fact, 
except the truly social species, perform their humble parts in the econ- 
omy of nature without teaching or example, for they are, for the most 
part, born orphans, and without relatives having experience to com- 
municate. The progeny of each year begins its independent cycle anew. 
Yet every individual performs more or less perfectly its allotted part, 
as did its ancestors for generation after generation. The correct view 
of the matter, and one which completely refutes the old teleological 
idea of the fixity of instinct, is that a certain number of individuals are, 
in point of fact, constantly departing from the lines of action and varia- 
tion most useful to the species, and that these are theindividuals which 
fail to perpetuate their kind and become eliminated through the general 
law of natural selection. 
Whether these actions be purely unconscious and automatic or more 
or less intelligent and conscious does not alter the fact that they are 
necessarily inherited. The habits and qualities that have been ac- 
quired by the individuals of each generation could have become fixed 
in no other way than through heredity. Many of these acts, which 
older naturalists explained by that evasive word *- instinctive,” may be 
the mere unconscious outcome of organization, comparable to vegetative 
growth: but insects exhibit all degrees of intelligence in their habits 
