46a THE SCIENTIFIC MONTHLY
trate, no generalization about the chromosomal stnictore and be- havior in the spermatogenesiB of species x of genus a can be accepted as fully valid until compared with the chromosomal structure and behavior of species M, N, 0, P, etc.^ of the same genus. And a like restriction must be placed on generalization about the reaction of species X to light, or to any other stimulus, or to its distribution in nature, and BO on.
To undertake the recital of special researches in support of this proposition vrould be to undertake the review of most of the recent in- vestigations in the provinces of biology mentioned. And notice this: The results of these researches look in the direction indicated despite the fact that in most cases the studies had little or no systematic inten^ tion. The great amount of evidence of this purport i& mostly incidental to other motives of investigation.
I would not be understood as advancing the hypothesis that every species of plants and animals differs from every other species to some extent in every attribute. What I afBrm is that the inductive evidence has now gone so far toward proving every sharply differentiated species to contain some differentia in all the main provinces of their structure and function, that to assume the absence of such differentia in any given case, is unwarranted.
Although in the interests of practical biology it is desirable that a searching examination of the whole range of biological knowledge should be made from the taxonomisfs standpoint, for a short theoretical discussion like that in which we are now engaged all that is incumbent upon us is to look, and that only cursorily, into a single province of biology, namely, biochemistry. This ia all that is necessary, I say, because the analysis of all phenomena of life into chemistry and physics being the ultimate goal of biology according to the now dominant biological philosophy, if it turns out that the chemical analysis is ex- haustive only when done on the basis of taxonomy, then it would seem to follow necessarily that all phenomena of structure and function intervening between the grosser morphological features with which taxon- omy has for the most part busied itself, and the ultimate physico- chemical features, must also be brought to a taxonomic basis before they are exhaustive.
It would be difficult to find a better example of weightiness of inductive evidence as dependent upon cumulation in particular lines, and convergence of different lines, than that presented by biochemistry bearing on the hypothesis here under consideration. Concerning the evidence of the chemical differentiation of species drawn from investi- gations on the blood of higher animals, recall the results of Beichart and Brown on the crystallization of hemoglobin. Here is one of their statements :
�� �
