194 EPOCHS IN THE HISTORY OP THE CONTEMPLATION 



tion. ( 306 ) As chemistry first begins when men have learnt 

 to employ mineral acids as powerful solvents, and as means of 

 liberating substances, the distillation of sea-water, described 

 by Alexander of Aphrodisias, in the reign of Caracalla, is 

 deserving of great attention. It indicates the path by which 

 men gradually arrived at the knowledge of the heterogeneity 

 of substances, their combination in chemical compounds, and 

 their reciprocal attractions or affinities. 



"We can only cite, as having advanced the knowledge of 

 organic nature, the anatomist Marinus, Eufus of Ephesus 

 who dissected apes and distinguished between nerves of 

 sensation and of motion, and Galen of Pergamos who eclipses 

 all other names. The natural history of animals by ^Eh'an of 

 Prseneste, and the poem treating of fishes written by Oppianus 

 of Cilicia, do not contain facts based on the author's own 

 examination, but only scattered notices derived from other 

 sources. It is hardly conceivable how the enormous multi- 

 tude ( 307 ) of rare animals, which, during four centuries, were 

 massacred in the Roman circus, elephants, rhinoceroses, 

 hippopotamuses, elks, lions, tigers, panthers, crocodiles, and 

 ostriches, should never have been rendered of any use to 

 comparative anatomy. I have already spoken of the merits of 

 Dioscorides in regard to the knowledge of collected plants : 

 his works exercised a powerful and long-enduring influence 

 on the botany and pharmaceutical chemistry of the Arabians. 

 The botanical garden of the Roman physician Antonius 

 Castor (who lived to upwards of a hundred years of age), 

 imitated, perhaps, from the botanical gardens of Theo- 

 phrastus and Mithridates, was probably of no greater scien- 

 tific use than the collection of fossil bones of the Emperor 



