646 ZOOLOGY SECT. 



Lemurs forming the order Quadrumana. Ehrenberg went 

 further, and divided the Animal Kingdom into Nations, i.e., 

 Mankind, and Animals. Even as late as 1857 Owen, as we have 

 already seen, made a distinct sub-class, Arckencephala, for Man, 

 the remaining Primates being included with the other higher 

 mammalian orders in the sub-class Gyrencephala. This view of 

 the isolated position of Man was connected with the theory of his 

 late appearance in time, and the fact of his co-existence with the 

 Mammoth and other extinct Mammals, first proved by Boucher 

 de Perthes in 1836 by the discovery of flint axes 20-30 feet 

 below the present surface, was for many years almost universally 

 denied. But Lyell's Antiquity of Man (1863) placed the 

 geological evidence on a sound footing, and the same was done for 

 the morphological evidence by Huxley, who, in his Man's Place in 

 Nature (1863), summed up the position by the statement, now 

 universally conceded, " that the structural differences which 

 separate Man from the Gorilla and the Chimpanzee are not so 

 great as those which separate the Gorilla from the lower Apes.j 

 Finally, Darwin, in his Descent of Man (1871), discussed the 

 question from every point of view, and concluded that " Man still 

 bears in his bodily frame the indelible stamp of his lowly 

 origin." 



It was also during the third quarter of the century that 

 the old doctrine of Abiogenesis or Spontaneous Generation, first 

 assaulted by Redi, but maintained by many naturalists from 

 Aristotle to Haeckel, was finally disposed of. The accurate 

 methods of Louis Pasteur, Lord Lister, John Tyndall, and 

 others, proved conclusively that the Bacteria, Monads, and other 

 lowly organisms which occur in putrefying substances do not arise 

 de novo, but are the product of germs in the floating dust of 

 the air by the exclusion of which putrefaction may be absolutely 

 prevented. 



During the last quarter of a century the progress of Zoology 

 has been profoundly influenced by the improvements in micro- 

 scopical methods, especially by the invention and perfection of 

 the microtome, the method of serial section-cutting, and the 

 various ways of preserving, imbedding, and staining tissues. The 

 microtome began as a simple contrivance for holding small objects 

 firmly while sections of them were cut by hand with a razor or 

 other knife, and has developed into the various modern forms of 

 the instrument in which the knife is fixed in a plane parallel to 

 the surface of the object, and the latter is raised mechanically by 

 small and equal increments as the sections are cut. In this way 

 perfectly regular sections are obtained of an even thickness not 

 exceeding the diameter of a cell. The method of imbedding 

 began by simply holding an object, too small or too soft to be 

 grasped by the fingers, between two pieces of carrot or pith, and 



