324 Analysis of Scientific Books. 



Philosophical Transactions, and, to him we also owe the discovery 

 of its possessing both male and female organs, and that it both 

 formed the ova in the ovarium, and afterwards impregnated them. 

 Having established this mode of generation in the teredines, he 

 found the lamprey, the common eel, and the conger, to be so 

 many different tribes of self impregnating animals. His merit 

 upon these subjects is, however, not all his own. He is indebted 

 to Mr. Bauer and Mr. Clift for their exertions in making drawings 

 illustrative of the facts he brings forward, and had he not been so 

 assisted, many doubts would certainly have hung over a great 

 part of his labours. 



He has been the means of enabling Mr. Bauer to immortalize 

 his name, by a series of drawings of internal parts of the earth 

 worm, and the progress that takes place in the formation of the 

 chick, during the process of incubation, which we may venture to 

 say will probably never be excelled. That the first part formed 

 in that process is the brain and spinal marrow ; the heart, arteries, 

 and the other parts, being all secondary, their structure not aris- 

 ing out of the molecule itself, but depending upon the supplies 

 derived from the yelk and albumen, are so many original facts of 

 the highest physiological importance. 



So much for our account of this valuable work, which were there 

 not one single word of letter press, would be a great accession to 

 anatomical science, since it contains more than three hundred 

 plates, by two such distinguished draftsmen as Bauer and Clift. 



On the synopsis, which is subjoined, bringing forward a new 

 scheme for the classification of animals, we must let the author 

 speak for himself, before we venture upon any remarks of our own. 



" Every step we advance in the acquirement of knowledge in 

 comparative anatomy, makes us better acquainted with the 

 defects that exist in the general systems at present before the 

 public. The truth becomes obvious, of there being no organ 

 belonging to an animal except the brain, that will bear us out in 

 affording characters for a general classification, the structure of 

 the other organs being varied whenever it was necessary to adapt 

 the animal to the climate which it is to inhabit, or the food on 

 Avhich it is to subsist ; and the brain we are not sufficiently ac- 

 quainted with to take as our guide. — There is only one fixed 

 principle that admits of being laid hold of for that purpose, with- 

 out which the whole scheme of nature would have been thrown 

 into confusion. The principle I allude to, is that which prevents 

 animals differently constructed from breeding with one another at 

 all, and does not allow those that are more nearly allied, to carry 

 on the breed beyond one generation. — The ovula of plants was to 

 botanists, what the molecule in the ovum of the human species and 

 quadrupeds is to the anatomist ; and till that knowledge was ac- 

 quired, and the changes produced in it by impregnation, were 



