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LECTUEE VIII. 



Comparative Examination of two species of monkey, Cehus alhifrons and 

 Cehus apella.—Skaa and Brain.— Other parts.— Affinities in Nature.— 

 Families.— Definition of Species, Vai-iety, and Eace.— Inbreeding of 

 Eaces and Species.— Mutability of Species.— Classification of Mankind. 

 — Eelation to the Ape.— The Human Kingdom according to Geoffroy 

 Saint-Hilau-e and Quatrefages. — Objections. 



Gentlemen, — It has ever been the custom to mete with a 

 different measure according to the object to be measured and 

 the disposition of the measurer. Sooner or later, however, 

 the fraud, even if it be a pious fraud, is detected and refuted. 

 This is more readily effected in science, which acknowledges 

 no other authority but its own laws resting upon well observed 

 facts. My object in this lecture is to apply to apes the same 

 method which we have followed as regards man. We shall 

 select for this purpose two species of apes generally acknow- 

 ledged as such, and shall examine their distinctive characters. 

 As already observed in a previous lecture, it is perfectly indif- 

 ferent what species are selected, as, considering the great 

 analogy in the physical structure of man and ape, the charac- 

 ters of the same parts are to be considered. Had we descended 

 to the lower orders and classes of the animal kingdom, it 

 might have been objected that the great modifications in 

 structure would require the application of different principles. 

 This does not apply to the ape, and if it can be shown that 

 such and such characters force us tt> assume different species in 

 apes, the same characters must lead to the assumption of dif- 

 ferent species in the human group. 



By mere accident, and not by choice, I have come into pos- 

 session of two species of the American Cebus (Kollaffen) . This 

 genus is very numerous ; it is spread over the whole South 



