256 



EXPLANAl 



depends ; for have we not seen Mr. Owen on the last 

 page affirming that the human embryo is first vermiform ? 

 — this meaning the form of the worms, a portion of the 

 class Annelides, in one of these lower divisions. That 

 all these divisions or sub-kingdoms are not represented 

 in the human embryo is an objection perfectly visionary, 

 for it is not necessary that all should be involved in the 

 ancestry, and therefore analogies to all are not to be look- 

 ed for. It may be said, then, there is no true difficulty 

 in this quarter. 



Perhaps no part of the arguments for the development, 

 theory has been more misapprehended, or misrepresented, 

 than this. It is continually said that the embryo, at any 

 of its particular stages, is not in reality the animal repre- 

 sented by that stage. The Edinburgh reviewer remarks, 

 with regard to the fish stage, " Were the embryo of a 

 mammal thrown off at that time into the water (of its own 

 temperature), it could not support life for a moment." 

 The brain of a child in the seventh month is also said to 

 he not the brain of any of the inferior animals, but a true 

 numan brain. The truth is, no one ever pretended that 

 there was such an identity. It is only said that there is 

 a resemblance in general character between the particular 

 embryotic stage of being, and the mature condition and 

 form of the appropriate inferior animal. The particular 

 adaptations, and the character of vital maturity, are all 

 wanting, and therefore it is that the embryo could not 

 live, as the inferior animal represented, if separated from 

 the parent, and really is not that inferior animal. 



It may be wall, before leaving this part of the subject, 

 to advert to a special charge which this writer, and at 

 least one other,* have brought forward : it is, that I as- 

 sume, not only that the organic germs of all creatures 

 are alike, but that they are identical. The Edinburgh 

 Review brings a contradiction to this proposition from 

 Dr. Clark. It is wholly unnecessary, for no such assump- 

 tion was ever made by me. The phrase used in the book 

 was, " Its primary positions [meaning the doctrines of 

 embryonic development] are that the embryos of all ani- 

 mals are not distinguishably different from each other ; " 

 which is a very different proposition. In several other 

 instances, propositions are thus misrepresented to i^ord 

 the glory of a visionary refutation. For example, the 

 * North American Review, April, 1845. 



