xvi THE HISTORY OF ZOOLOGY 665 



form of genealogical trees, and he was the first to employ the 

 method of introducing hypothetical ancestral forms, wherever 

 they might be wanted to complete the connection between known 

 groups. He may be said, in fact, to have founded a school of 

 deductive zoology, the phylogenetic speculations of which are 

 often as ingenious and suggestive as they are transient. The 

 student must, however, bear in mind that Archi-molluscs, Ideal 

 Craniates, and Pro-mammalia are mere figments of the imagina- 

 tion, and have no more real existence than the " Divine Arche- 

 types " of an earlier school of thought. 



One result of the new views on species, very obvious in the 

 writings of both Huxley and Haeckel, was the marked alteration 

 in the position assigned to Man in the animal series. Linnaeus 

 considered Homo as a genus of his order Primates, equivalent to 

 Simia, Lemur, &c. ; but Cuvier took the retrograde step of erecting 

 a distinct order, Bimana, to contain Man alone, the Apes and 

 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, Archencephala, 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." 

 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 last 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. 



