BIOGRAPHICAL SKETCH OF HENRY MILNE-EDWARDS. 725 



ing' all the {'ombinatioiis comprised in those limits. But the variatious 

 themselves are not pro(luce<l by chance, — and just at this point this 

 author begins to present original views,— they take place through a 

 principle similar to that which governs the mechauical industrj'- and 

 organization of human societies, the principle of the division of labor. 

 This is in a manner l)orrowed by political economy. 



When human societies are in their primitive stage each man is 

 obliged to provide for his separate needs, he must i)rocure his food, 

 construct his dwelling, manufacture his clothing and all objects neces- 

 sary to his life, health, and personal defense. Among civilized peoples, 

 on the contrary, each member of the association devotes himself to the 

 accomi)lishment of a fixed portion of this labor, but he performs this 

 with a greater degree of economy and perfection; thus the social 

 machine becomes co-ordinated and hierarchical while being perfected. 



To carry these ideas into the animal order every living creature is 

 fitted to procure food and to repi'oduce its kind, these fundamental 

 functions being common to vegetables and animals. The distinctive 

 feature of the latter is that they are capable of feeling and of motion, 

 these functions being fulfilled in a way that leads to the persistence of 

 the individual and of the species; it may be said that every animal is 

 absolutely perfect. The human mind however conceives of different 

 degrees in this perfection. At the foot of the ladder we perceive 

 animals like sponges and certain zoophytes constituting a mass of 

 uniform appearance qualified for the same functions throughout all 

 the parts, while performing apparently automatic movements. The 

 same tissue seizes the food to be digested, contracts, dilates, breathes 

 at the expense of the surrounding watery medium, appears to be 

 affected by the sensations of light and heat, is multiplied and repro- 

 duced in the case of spontaneous or accidental fracture. A hydroid 

 polyp may be cut in i)ieces and each separate piece will be capable 

 of carrying on without change an individual existence similar to that 

 of the original body. By this it will be seen that the function 

 existed before the organ ; far from being the i)roduct of the organ it 

 serves to fit it for a special purpose. ! n fact, by the side of these simple 

 animals, such as sponges or hydroid polyps, we meet with others in 

 which each function begins to be set apart for special purposes. Diges- 

 tion is performed in special cavities, generation is effected in a distinct 

 manner; circulation, respiiation, power of motion, all the sensations 

 acquire in succession their proper working api)aratns, to be in turn 

 divided into different parts that are destined to the performance of one 

 of the acts of which the whole constitutes the general function. 



Thus digestion first taking })lace in an interior cavity provided with 

 a tissue similar to that which constitutes the general surface of the 

 body, soon acquires a special cavity, a stomach at first adventitious 

 and temporary, but becoming permanent in other species. In propor 

 tiou as the scale of life ascends the animal is at the proper time pro- 



