280 NATURAL HISTORY OF ORGANIZED BODIES 



imagination is lost in conjectures on tlie function proper to each. It is now 

 necessary to see these things in action, each executing the Avork for which it is 

 adapted. The catalogue has been drawn up with suflicient exactness for present 

 needs. To-day the current no longer tends to classification, it is directed to the 

 study of the functions of life ; that is to say, the play of the organs which anatoni}* 

 has disclosed to us. This study of the phenomena vvhich take place in living 

 beings is ordinarily called physiology, or, more con'ectly, biology. 



All organized beings live ; animals or plants all accomplish a series of acts 

 from their origin to their dissolution ; but life is interpreted in them by mani- 

 festations as varied as their organization itself. 



It may be said that biology is the offspring of anatomy, for it was from the 

 form of the organs that man was first inspired with the comprehension of the 

 function of each of them. This influence of anatomy gave to biology in the 

 first instance a deductive character from which, even in our day, it finds diffi- 

 culty in disengaging itself. It is tnie that when we see the anangement of the 

 articulating surfaces which unite the different parts of the skeleton, we readily 

 comprehend the function of those organs; we see how each bone moves upon its 

 contiguous bone, and this in itself explains the varied positions which certain 

 portions of the body may assume. But the action of the muscles was much more 

 difficult to be comprehended. Aristotle himself knew it not. The representa- 

 tive of ancient science, the founder of comparative anatomy, most have con- 

 stantly observed the extreme variety of muscular development in different species 

 of animals, and yet this anatomical principle ctmveyed to liim no idea of the 

 function of the muscle. It was reserved for Erasistratus, grandson of Aristotle, 

 to discover first the elementary fact, that a muscle contracts in order to produce 

 motion. The role of the other organs was still more obscitre ; but in regard to 

 these, not satisfied with ignorance, inquirers accumulated in the name of science 

 the most foolish suppositions. The viscera, in ])articular, were endowed with 

 singular functions ; each of them lodged one of the properties of the soul. In the 

 head resided reason, in the heart courage and choler, in the liver concupiscence, 

 and so with different organs. Such ideas, of course, could never have been 

 inspired by anatomy, and they had, in effect, another source. Philosophers have 

 by no means been insensible to the attractions of the mysterious and incompre- 

 hensible; psychology is more ancient than the sciences, and Aristotle had 

 received from Plato a whole system ready made. It was thought indispensably 

 necessary to lodge three souls in the human body, and each of these had several 

 properties which could not be left without a habitat. Thus it is that mystical 

 tradition has imposed even on those who have conscientiously sought to place 

 themselves in direct relations with natitre. 



I would have willingly passed in silence these singular tendencies of tho 

 human mind to depart from the domain of real facts and to yield to the caprices 

 of imagination; but the question relates not to a passing eiTor to which time has 

 already rendered justice. The ideas of Plato have a hundred times changed 

 their fonxi, but they have been transmitted from age to age ; they prevail at 

 this day under the fonn of viialism ; that is to say, the doctrine which pretends 

 to have explained every phenomenon of life when it has pronounced such or such 

 a phenomenon to be the effect of a particular ^jro^jfrf^?/ of the living being. This 

 doctrine I shall not stop to combat; quite enough has been vainly said in 

 attempting to confute those who do not choose to be convinced. It is safe to 

 assimie, however, that the vitalistic school is at present condemned for its steril- 

 ity; that it loses ground every day, while the number of those is daily increas- 

 ing A\ho demand fronr the rigorous observation of facts and from experiment the 

 solution of the problems of biology. 



It woitld be more interesting to follow through its sttccessive stages the devel- 

 opment of the school of experimenters. To find its origin, we must go back to 

 remote periods. Surprising it is, that the two opposite tendencies which Lave 



