NATURAL HISTORY OF ORGANIZED CODIES. 285 



the diapliragm or walls of the breast of an animal, alive or dead, were pierced ; 

 there is now nothing obscure in the nature of this effect. The same cause 

 explains also many phenomena relating- to the exchange incessantly produced 

 between the gases of the blood and the atmospheric air, the action of respiration 

 on the course of the blood, &c. IMechanics elucidates the muscular phenomena, 

 and in general all the movements produced by animals. The circulation of the 

 blood borrows from hydrodynamics the explanation of everything relating to the 

 movement of the sanguineous fluid. Without chemistry, what ideas could we 

 possess respecting the digestive functions, the offices of respiration, the function 

 of the glands'? Optics and acoustics are treated, in the Avorks on physiology, in 

 the same manner as in those on physics. Finally, the laws of electricity acquire 

 every day more "mportance in the interpretation of the nervous phenomena. 



All this proves the reciprocal dependence {solklarif/j) of the sciences; it shows 

 that it is necessary to separate them as little as possible, that the tendency should 

 be to their simplilication, to the reduction into general laws in order to render 

 them easily accessible to every one. 



A very important point, for it is decisive of success or failure in scientific 

 researches, is the choice of a good method. On this subject it is necessary to 

 be guarded against a very common error. We become habituated generally by 

 the usual processes of demonstration to pass from the simple to the composite, 

 to start from a well established principle in order to an'ive, from one deduction 

 to another, at the demonstration of more complex propositions. It is in this way 

 that the theorems of geometry are successfully demonstrated; but is it by this 

 method that a scienceis established ? Far otherwise; nor do those who mahe 

 discoveries in the natural sciences proceed in this manner. They observe a 

 great number of facts, compare them, place them side by side, seek the condi- 

 tions which modify each phenomenon, and succeed only in the last place in 

 finding a principle or a laAv which may guide the understanding in the midst of 

 an embarrassing complexity. 



Medicine, a science whicli touches us so nearly, since it deals Avith the troubles 

 which occur in the functions of life, Avas long misled by that false method 

 Avhich generates s>jsfems. Starting from a principle supposed to be true, it pro- 

 ceeded Avith the most irreproachable logic to heap deductions upon deductions, 

 till the moment Avhen error became so obvious that the Avhole fabric collapsed 

 at once, and the Avork Avas to be commenced ancAv. It Avas a pure metaphor 

 that AATought the evil : " It Avas proposed to construct the science, and a corner- 

 stone AA-as to be sought to support the edifice." But by Avhat right, among so 

 many materials, Avas one stone to be taken for this purpose sooner than another ? 

 By what token Avas it to be recognized as the real "base of the structure 1 Cer- 

 tainly, by none. If there must be a metaphor, I Avould prefer to comp^ire the 

 study of the natural sciences to the labor of the archeologists in deciphering 

 inscriptions traced in an unknoAvu language. They try, turn by turn, several 

 senses for each sign ; they seek assistance at the same time from the conditions 

 under Avhich each inscription has been found, and from the analogy it presents 

 AA'ith inscriptions already knoAvn, and they arrive only in the last place at a 

 kuoAvledge of the principles by Avhich they teach others to decipher the strange 

 language. 



In every science progress is only to be obtained by the cra])loyment of certain pro- 

 cesses Avhich act like poAverful levers in the service of the human mind : anal//sis, 

 Avhich serves for research, and sijntJicsis, which is employed to verify the results 

 of analysis, or to set in a more simple light a truth already discovered. But 

 everything is susceptible of improvement, even the means Avhich are at our dis- 

 posal for the realization of further progress. I propose, therefore, summarily 

 to state the present resources of analysis and synthesis, instruments Avhich are 

 so constantly to be handled by the teachers as Avell as cultivators of science. 



Analijsis consists in reducing to its most simple elements a phenomenon too 



