the Introduction of New Species. 195 



the zoologist, may there be buried^ till future revolutions may 

 raise them in their turn above the waters, to afford materials for 

 the study of whatever race of intelligent beings may then have 

 succeeded us. These considerations must lead us to the con- 

 clusion, that our knowledge of the whole series of the former 

 inhabitants of the earth is necessarily most imperfect and frag- 

 mentary, — as much so as our knowledge of the present organic 

 world would be, were we forced to make our collections and 

 observations only in spots equally limited in area and in number 

 with those actually laid open for the collection of fossils. Now, 

 the hypothesis of Professor Forbes is essentially one that assumes 

 to a great extent the completeness of our knowledge of the whole 

 series of organic beings which have existed on the earth. This 

 appears to be a fatal objection to it, independently of all other 

 considerations. It may be said that the same objections exist 

 against every theory on such a subject, but this is not neces- 

 sarily the case. The hypothesis put forward in this paper 

 depends in no degree upon the completeness of our knowledge 

 of the former condition of the organic world, but takes what 

 facts we have as fragments of a vast whole, and deduces from 

 them something of the nature and proportions of that whole 

 which we can never know in detail. It is founded upon isolated 

 groups of facts, recognizes their isolation, and endeavours to 

 deduce from them the nature of the intervening portions. 



Another important series of facts, quite in accordance with, 

 and even necessary deductions from, the law now developed, are 

 those of rudimentary organs. That these really do exist, and in 

 most cases have no special function in the animal oeconomy, is 

 admitted by the first authorities in comparative anatomy. The 

 minute limbs hidden beneath the skin in many of the snake-like 

 lizards, the anal hooks of the boa constrictor, the complete series 

 of jointed finger-bones in the paddle of the Manatus and whale, 

 are a few of the most familiar instances. In botany a similar 

 class of facts has been long recognized. Abortive stamens, 

 rudimentary floral envelopes and undeveloped carpels, are of the 

 most frequent occurrence. To every thoughtful naturalist the 

 question must arise, What are these for ? What have they to 

 do with the great laws of creation ? Do they not teach us 

 something of the system of Nature ? If each species has been 

 created independently, and without any necessary relations with 

 pre-existing species, what do these rudiments, these apparent 

 imperfections mean ? There must be a cause for them ; they 

 must be the necessary results of some great natural law. Now, 

 if, as it has been endeavoured to be shown, the great law which 

 has regulated the peopling of the earth with animal and vege- 

 table life is, that every change shall be gradual ; that no new 



