NATURAL HISTORY OF ORGANIZED BODIES. 291 



occurred tliat Harvey observed tlie beatings of tlie lieart ; and in another, 

 where a gastric fistula had been formed, that Beaumont conducted his memor- 

 able studies on digestion. The vices of congenital conformation furnish us 

 with numerous indications, not only on the subject of cnibryogcnii, but also in 

 relation to certain functions, such as those of the nervous S3^stem, respiration, 

 and circulation, which produce the movements of the cephalorachidian liquid, &c. 

 The above is but a summary statement of the means of analysis at our dis- 

 posal at the present time. Our resources, it will be seen, are great, and furnish 

 a guarantee of success in researches yet to be undertaken. I would repeat, in 

 conclusion, what I have before said, that progress is visibly taking place through 

 the fusion of the sciences, and for us, naturalists and biologists, resolves itself 

 into the facilities which we every day derive from physics and chemistry. 

 The time will come, no doubt, when we shall be able in our turn to furnish to 

 those sciences new elements of progress. But, for the moment, wc are their 

 debtors, for the reason that the physical and chemical sciences, more simple than 

 ours, and long disengaged from the bad methods by which we have been misled, 

 are to-day more advanced than biology, in the sense that they arrive more readily 

 at exact ideas of the phenomena Avhicli they study. It is only after having 

 fruitlessly employed in the study of the phenomena of life the methods supplied 

 by physics and chemistry that we shall have any right to invoke the intervention 

 of extra-physical causes for the explanation of the vital phenomena ; and it is 

 not difficult to see how far we are from having exhausted the resources which 

 physical and chemical analysis now places at our disposal. 



III. — EXPERIMEXTAL SYNTHESIS IX THE NATURAL SCIENCES. 



In speaking of the processes Avhich the human mind emploj'S in scientific 

 researches, I have mentioned analysis and synthesis. We have thus far treated 

 of analysis ; we have considered it in its progressive improvements, and know, 

 in a general manner, the immense resources which it has at its command. 



It remains to inquire the meaning of synthesis and the services which it is capable 

 of rendering. It has already been seen that it is not a method of research ; that 

 a science which should propose to found itself upon sj'nthesis, by setting out 

 upon principles established a priori, would incur the peril of going widely astray. 

 But nothing of this sort is to be apprehended when analj'sis has finished its 

 work and has put us in possession of a large number of facts, well established. 

 It is then that the office of sjaithesis commences. Synthesis is the opposite of 

 analysis; it reconstructs what has been decomposed. This is the most general 

 definition of the method. But to give a more complete idea of it, it is well to 

 follow it in its different apjjlications. We Avill first examine experimental syn- 

 thesis, in so far as it serves to control the results of analysis by reproducing a 

 phenomenon through a reassemblage of the conditions of its existence. After- 

 wards we shall pass to synthesis properly so called, being such as it is defined 

 by scholastics, and which collects particular facts into general laws. 



Experimental synthesis recompounds that which has been decomposed into its 

 different elements. The chemist, for instance, when he has decomposed water 

 by means of analysis and has separated it into oxygen and hydrogen, can 

 recombine those two gases. He has effected the synthesis of water. In 

 this second experiment, then, is found the most satisfactory demonstration of the 

 exactness of the first. Synthesis has served for the proof of analysis. 



In organic chemistry the introduction of synthesis is altogether recent, but it 

 has effected in this branch of science a real revolution. In the last century, 

 chemists believed that organic matter was formed in animals and plants by virtue 

 of forces different from those which govern unorganized matter. Buffon even 

 recognized an animated organic matter, destined to furnish unceasingly the 

 material of beings endowed with organization. As late as 1849, Berzelius still 

 admitted of special chemical laws in organized nature. 



