JEAN LOUIS RODOLPHE AGASSIZ. 485 



ing material for a series of Contributions to the Natural His- 

 tory of the United States. In 1857 appeared two volumes of 

 these contributions ; the first containing an Essay on Classifi- 

 cation and the history of the North American Testudinata ; 

 the second on the Embryology of the Turtle, and was illustrated 

 with thirty-four plates. 



In the essay on Classification, Agassiz affirms that Nature is 

 but the expression of the thought of the Creator, and that a 

 true classification will be found to be but an unfolding of the 

 plan of creation, as expressed in living realities ; that these re- 

 alities do not exist in consequence of the continued agency of 

 physical causes, but appear successively by the immediate in- 

 tervention of the Creator. We find in Nature a progressive 

 series, from lower to higher forms ; but it is not a uniform 

 progress for the animal kingdom as a whole; neither is it 

 a linear progress for the branches or classes, but a progress 

 in which each type has usually been introduced by the crea- 

 tion of species belonging to one of its higher groups, for the 

 earliest representatives of a class do not always seem to be 

 the lowest. Yet, notwithstanding these downward steps, the 

 progress has continually tended toward the production of 

 higher and higher types, culminating at last in Man. 



The third volume of the Contributions appeared in 1860, 

 and was devoted to the class of Acalephce, the author treating 

 specially of the order Ctenophorcz. The fourth volume, issued 

 in 1862, concluded the Acalepha. The plan of the work had 

 contemplated ten volumes, but only these four were com- 

 pleted in his lifetime. A fifth volume on North American star- 

 fishes appeared after his death. 



From his early student days Agassiz's collections were a 

 source of care and solicitude to him. In a letter written from 

 Munich, he values his accumulations at two hundred louis, near 

 one thousand dollars, and calls this a low estimate. His grand- 

 father gave them houseroom for a while, and they, with later 

 additions, were finally disposed of to the Lyceum of Neuchatel 

 when Agassiz entered upon his professorship there. Starting 

 anew after he came to America, he gathered specimens more 

 rapidly than before. During his first years at Cambridge an 

 old boathouse on the bank of the Charles River served as a 

 storehouse for them. By 1850 they had acquired such volume 

 as to make a severe drain upon his income merely to preserve 



