280 NATURAL HISTORY OF ORGANIZED BODIES 



ima£i'i nation is lost in conjectures on the function proper to eacli. It is now 

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

 adapted. The catalogue has been drawn np with sufficient 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 anatomy 

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

 beings is ordinarily called physiology, or, more correctly, 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 

 fonn 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 tlie 

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

 culty in disengaging itself. It is true that when we see the arrangement of the 

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

 comprehend the function oi those oi'gans ; we see how each bone moves upon its 

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

 portions of the V)ody 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, must have con- 

 stanth^ observed the extreme variety of muscular development in different species 

 of animals, and yet this anatomical principle conveyed 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 obscure ; but in regard to 

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

 the most foolish suppositions. The viscera, in particular, were endowed with 

 singrJar functions ; each of them lodged one of tlie 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, coukl never have been 

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

 l>y no means been insensible to the attractions of the mysterious and incomjire- 

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

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

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

 properties v>"hich 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 nature. 



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

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

 of imagination ; l)ut 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 form, but they have been transmitted from age to age ; they prevail at 

 this day under the form of vitalism ; 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 2))'0j)C)iy 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 clioose to be convinced. It is safe to 

 assume, 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 who demand from the rigorous observation of facts and from experiment the 

 solution of the problems of 1)iology. 



It would be more interesting to follow through its successive 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 have 



