28 THE EVOLUTION OF MAN. 



It is certain, for example, that he was thoroughly 

 acquainted with the entirely peculiar method of propagation 

 and development of the Cuttle-fishes, or Cephalapods, the 

 embryo of which has a bag of yelk protruding from the 

 mouth. He knew, also, that embryos of Bees can be 

 developed from the egg even when it has not been fertilized. 

 The so-called parthenogenesis, or virginal generation, of 

 Bees has been proved in our days only lately by the 

 meritorious zoologist, Siebold, of Munich, who also showed 

 that male Bees develop from unimpregnated, and female 

 bees only from impregnated eggs.-^^ Ai'istotle further 

 relates that some Fishes (of the species Serranus) are 

 hermaphrodites, inasmuch as each individual has male 

 and female organs, and impregnates itself. This fact, also, 

 has only lately been established. He also knew that the 

 embryos of several species of Sharks are connected with 

 the mother's womb by a sort of placenta — an organ of 

 nourishment, full of blood, which otherwise occurs only 

 in Man and the higher Mammals. This placenta of the 

 Shark was for a long time considered mythical, until, in 

 1839, Johannes Mliller, of Berlin, proved it to be a fact. 

 We might quote many other remarkable observations from 

 Aristotle's account of Evolution, which would prove the 

 accuracy of this great naturalist's acquaintance with onto- 

 genetic investigations, and the great degree in which he 

 was in advance of subsequent times in this respect. 



In most of his observations he was not satisfied with 

 merely stating the facts, but he added reflections on their 

 significance. Some of these theoretical thoughts are of 

 special interest, because they indicate a right fundamental 

 perception of the nature of the processes of evolution. He 



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