SUMMER AT NAHANT. 647 



frequently sigh for another session in your 

 museum, and it is not improbable that I shall 

 solicit an invitation from you in a few years, 

 in order to revise my views of the whole sub- 

 ject in connection with what I am now learn- 

 ing of the living fishes. By the way, I have 

 eleven hundred colored drawings of the spe- 

 cies of Brazil made from life by my old friend 

 Burkhardt, who accompanied me on this jour- 

 ney. 



My recent studies have made me more ad- 

 verse than ever to the new scientific doctrines 

 which are flourishing now in England. This 

 sensational zeal reminds me of what I expe- 

 rienced as a young man in Germany, when 

 the physio-philosophy of Oken had invaded 

 every centre of scientific activity ; and yet, 

 what is there left of it? I trust to outlive 

 this mania also. As usual, I do not ask be- 

 forehand what you think of it, and I may 

 have put my hand into a hornet's nest ; but 

 you know your old friend Agass., and will 

 forgive him if he hits a tender spot. . . . 



The summer of 1867 was passed very tran- 

 quilly at his Nahant laboratory, in that quiet 

 work with his specimens and his microscope 

 which pleased him best. The following letter 



