S32 Zoological Society : — 



principle of permanence from producing monotony. Whence comes 

 this principle of permanence ? I look to Mr. Darwin for an answer, in 

 vain. All that he says on this point amounts only to the position that 

 the progeny of nearly allied species are not always sterile. That the 

 prescrvatory tendency does not necessarily accompany a given amount 

 of external difference is clear ; for man can produce in living organisms 

 external differences greater than those associated in nature with this 

 principle of permanence, without calling that principle into action. 

 To attribute it to the greater length of time occupied in the formation 

 of natural species than in that of a variety, is to make an assumption 

 wholly destitute of proof, and indeed inconsistent with a very beau- 

 tiful and essential part of jNIr. Darwin's hypothesis, namely, the doc- 

 trine that the living princi{)le never loses its energy, and that the 

 power of life now at work on our globe has been transmitted, 

 imchanged in its essence, though infinitely richer in its manifestations, 

 from the first inhabitants of the earth to the generations inhabiting 

 it at the present day. 



If then JNIr. Darwin may appeal to the principle of change dis- 

 closed in living organisms, as a " true cause," capable of accounting 

 for the mutual aflinities of species by the supposition of descent from 

 a common origin, those who are opposed to his views are no less 

 entitled to appeal to the principle of ])ernianence, disclosed in these 

 organisms, as a real force, not to be explained away, but requiring to 

 he reconciled with the principle of change in any theory which shall 

 satisfactorily account for the origin of species. 



It appears to me that this reconciUation may he effected through 

 the intervention of a conception proposed by one of whose labours 

 and reputation we are justly proud, as an ex[)lanation of the "homo- 

 logies" of structure, which he has profoundly illustrated. I mean 

 the conception of the typical character pervading all organic life. 

 But to make this apparent, I must premise some remarks on the 

 characteristics of natural tyj)es. The types of nature must be care- 

 fully distinguished from the types of art. The types of art are forms 

 realized in their perfection in some particular individual. A Phidias 

 may produce a Jupiter, a Minerva, or a Venus, as the perfect out- 

 ward embodiment of the ideal of jVIajesty, or Wisdom, or Grace. A 

 Danecker may toil for years, in labour with his conception of the 

 head of Christ. But in each case, the type, when realized, is a fixed, 

 individualized object, expressing some one predominant characteristic, 

 to which all others, though not necessarily lost, are subordinate. The 

 types of nature are, as I conceive, ideals not of external form, but of 

 internal relations, each realized in countless modifications of forms 

 diflfering from one another in infinitely varied particulars, but 

 balanced aroimd central points common to them all. But the pre- 

 servation of this balance depends u])on the aptness of each variety of 

 the type for interbreeding with all the rest, and thus perpetually 

 rccombiningits own peculiarities with theirs. If any of the varieties 

 hv the action and reaction of which a type is preserved become locally 

 distinct from the others, subtypes will arise ; as we find to be the 

 case in mankind. The original type becomes the centre of a circle 



