724 BIOGRAPHICAL SKETCH OF HENRY MILNE-EDWARDS. 



his indebteduess to tliein than ^mjioU liiin.self under the banner of a 

 master. By reason of these manifold circumstances a book of a general 

 character, a compilation with whatever care it may have been prepared, 

 will seldom live beyond the generation for which it was compiled; 

 sooner or later it will be replaced by one of the same kind more in 

 touch with the works of the day and itself destined to a transient fame. 



IV. — HIS ZOOLOGICAL PHILOSOPHY. 



It is better to dwell upon the individual and original ideas of Milne- 

 Edwards tliat will remain associated with his name and to which he 

 has given definite and lasting expression, if, indeed, any theory can 

 lay claim to such a character in the incessant changes and revolutions 

 of human knowledge. Milne-Edwards, in fact, had been led by his 

 indefatigable labors and his ever improving methods of iiistruction to 

 explain certain general theories respecting the agencies which control 

 the innumerable metamorphoses of organs and their correlative func- 

 tions. He took up these theories again in one of the most remark- 

 able of his smaller books, published in 1858, under the title of "An 

 Introduction to Ueneral Zoology, or Notes on the Tendencies of Nature 

 in the Constituti-on of the Animal Kingdom." 



This title itself is characteristic of the man and of his times. In 

 fact, nature is now rarely spoken of as if it were regarded in the light 

 of an actual personality having a character, te;ideucies, and caprices 

 after the fashioii of a moral being. Whether right or wrong, language 

 implying that nature is a working machine has been substituted for 

 these sentimental expressions, but at bottom these later ideas have no 

 less significance. In reality, whatever the language used, the question 

 in point is always to examine and ascertain the same essential rela- 

 tions between organic systems and functions; facts flow out of these 

 relations, or, as 1 might say, out of the investigation of living beings 

 and the phenomena of which they are the seat. Only instead of seeking 

 to discover in them a pre conceived design for some special and often 

 puerile purpose, the scientist recognizes with admiration the harmony 

 and general co-ordination in the permanent regularity of natural laws, 

 the condition of the persistence of human beings, alike as individual 

 types and as successive generations. 



One of the simplest and most interesting of tliese necessary rela- 

 tions was discovered by Milne-Edwards, who traced its consequences 

 with wonderful quickness of perception. This was the principle of the 

 division of labor, which he first observed in his studies of crustaceans 

 to operate both in the development of the types of animal species and 

 in the perfecting of those types. 



To start from this point of departure, two laws, according to Milne- 

 Edwards, are discoverable in animal organisms: a tendency to varia- 

 tion, or the law of change, and the law of economy by virtue of which 

 this variation takes jjlace in each type within given limits^ exhaust- 



