NATURAL HISTORY OF SEVENTEENTH CENT. 239 



{Viviparous Quadrupeds. 

 Whales. 

 Birds. 



[ Heart with one ventricle. Reptiles. 

 Breathing by gills .... Fishes. 



Animals having 

 red blood. 



!( Mollusca. 

 Greater . . '. . . . j Crustacea. 

 (Shell-Fish. 

 Less Insects. 



Ray's first botanical work appeared in 1660, but his most extensive 

 and laborious production was a " General History of Plants," in a thick 

 folio volume, published in 1704, giving everything known about the 

 subject, and containing notices of no fewer than eighteen thousand 

 six hundred plants. An elaborate attempt to classify plants in natural 

 orders, founded chiefly on the characters of the fruits, was published 

 by Ray in 1668. Plants were first divided into two sets, namely, 

 Herbs in one, Trees and Shrubs in the other. The first set included 

 twenty-five classes, the second eight classes. 



Ray died in 1705, at the age of seventy-seven, and with him we 

 may conclude the history of botany and zoology to the end of the 

 seventeenth century, so far, at least, as those sciences are connected 

 with description and classification. But it is evident that classification, 

 even if that were the only object of these branches of natural history, 

 could have no value if founded merely on external forms. A know- 

 ledge of the structure of the various organs possessed by animals and 

 vegetables, and of the several functions of those organs, is as essential 

 for any truly scientific classification of living things as it is necessary 

 for the understanding of the nature of any given animal or vegetable, 

 or the right conception of animal and vegetable life in general. Here 

 we have to note a few of the steps by which the knowledge of ana- 

 tomy and physiology, both of vegetables and animals, has advanced. 



In Aristotle's treatise on animals there are contained many facts 

 of comparative anatomy, and it is probable that such knowledge as 

 the ancients possessed of human anatomy was principally obtained, as 

 far as dissection was necessary, by the dissection of animals. The 

 ideas of the ancient Greeks concerning rites to which the bodies of the 

 dead were entitled, and the guilt which was ascribed to any omission 

 of duty in this respect, must have left to the physicians few opportu- 

 nities of dissecting human bodies, even if any persons were bold 

 enough to venture. Hippocrates, the father of medicine, has so little 

 to say about anatomy, that it is considered doubtful whether he even 

 had at any time attempted to dissect the body of an animal. CELSUS 

 (<r. A.D. 20), in his system of medicine, has as little knowledge of the struc- 

 ture of the body as his predecessor. GALEN (130 200), however, the 

 great medical oracle of the Middle Ages, left an anatomical account of 

 the human body/which remained unsurpassed for a,thousand years ; for 



