The Class-Book of Chemistry. 57 



brought up to regard the Bible not only as the au- 

 thoritative basis of religion, but also as absolutely 

 correct in its science. His thought upon these sub- 

 jects was greatly stimulated by the first lectures de- 

 livered in New York by Professor Agassiz. To these 

 lectures, introductory to the study of natural history, 

 Miss Youmans escorted her brother soon after her 

 arrival in the city. They were delivered to crowded 

 audiences in the hall of the College of Physicians and 

 Surgeons, in Crosby Street. Every fitting occasion 

 in the course of the lectures was used by Agassiz to 

 illustrate his favourite conception of the truths of 

 science as the thoughts of God. People were so 

 eager to hear him express an opinion on the develop- 

 ment theory, that in his sixth lecture he felt con- 

 strained to turn aside from his systematic exposition, 

 and say : 



But with the progress, of species,' as we find them in 

 different geological strata, the question is, Can we find in 

 Nature external causes which will produce these changes ? 

 And, again, Can we refer these successive appearances of 

 different types to the influences of external causes ? I say 

 No ; because, since man has studied Nature, he has never 

 seen any species modified under external influences. 



And again : 



These views — to which I shall recur when I come to 

 speak of the position of man in Nature, and of his relations 

 to the animal kingdom — disagree entirely with the views, 

 and have not the slightest alliance with the views, of a 

 work which is very much spoken of [The Vestiges of Crea- 

 tion], but which I consider entirely unworthy of notice by 

 any serious scientific man, because it is made up of old- 

 fashioned views which have been brought before the notice 



