82 AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. 



faced and unblurred. Man, by receiving a plastic body, in accordance with a law 

 that species most capable of domestication should necessarily be most pliant, was 

 fitted to take the whole earth as his dominion, and live under every zone. And 

 surely it would have been a very clumsy method of accomplishing the same result, 

 to have made him of many species, all admitting of indefinite or nearly indefinite 

 hybridization, in direct opposition to a grand principle elsewhere recognized in the 

 organic Ijingdoms. It would have been using a process that produces impotence 

 or nothing among animals, for the perpetuation and progress, of the human race. 



There are other ways of accounting for the limited productiveness of the mulatto, 

 without appealing to a distinction of species. There are causes, independent of 

 mixture, which are making the Indian to melt away before the white man, the 

 Sandwich Islander and all savage people to sink into the ground before the power 

 and energy of higher intelligence. They disappear like plants beneath those 

 of stronger root and growth, being depressed morally, intellectually andjshysically, 

 contaminated by new vices, tainted variously by foreign disease, and dwindled in 

 all their hopes, and aims, and means of progress, through an overshadowing race. 



We have therefore reason to believe from man's fertile intermixtiu'e, that he is 

 one in species ; and that all organic species are divine appointments which cannot 

 be obliterated, unless by annihilating the individuals representing the species. 



It may be said, that different species in the inorganic world combine so as to 

 form new units, and why may they not in the organic ? It is true they combine, 

 but not by indefinite blendings. There is a definite law of multiples, and this is the 

 central idea in the system of inorganic nature. In organic nature, such a law of 

 multiples, if existing, would be general, as in the inorganic ; it would be an essential 

 part of the system, and should be easily verified, while, in fact, observation lends it 

 no support, not even enough to have suggested the hypothesis. 



In one kingdom, the inorganic, there is multiplication of lands of units by com- 

 bination, according to the law of multiples, and no reproduction ; while in the or- 

 ganic, there is reproduction of like from like and no multiplication of kinds by 

 combination. And thus the two departments of living and dead nature widely 

 diverge. 



Neither does the possibitity of mere mixtur; among inorganic substances afford 

 any analogy to sustain the idea of possible hybrid mixture indefinitely perpetuated 

 among living beings. The mechanical aggregation of units that make up ordinary 

 mixture, is one thing; and the combination that would alter a germ, one of the 

 units in organic species, even to its fundamental nature, is quite another. This last 

 is not aggregation. It is as different from mere mixture as is chemical combina- 

 tion, and stands somewhat in the same relation, so that the analogy has no bearing 

 on the question. 



3. Variations of species. 

 . But there are variations in species, and this is our next topic. The principles 

 already considered teach, as we believe, that each species has its specific value as a 

 unit, which is essentially permanent or indestructible by any natural source of 

 change ; and we have, therefore, to admit in the outset, if these principles are true, 

 that variai'ions have their limits, and cannot extend to the obliteration of the fund- 

 amental characteristics of a species. 



To understand these variations, we may again appeal to general truths. 



Variation is a characteristic of all things fiuite ; and is involved in the vei-y 



