58 



If a machine can be perfectly known, only alter taking it to pieces? 

 down to its simplest elements ; if the mechanism of the whole action is 

 conceived, only by separately studying the action of each different part, 

 Comparative Anatomy, by aid of which we can study, in the great chain 

 which the animal kinds compose, the separate action of each organ, ap- 

 preciate its absolute or relative importance, consider it, at first, insulated 

 and reduced, so to speak, to its own powers, in order to determine what 

 part it bears in the carrying on of a function ; Comparative Anatomy 

 is of absolute necessity to him who would make great progress in the 

 knowledge of man ; it may be looked upon as a sort of analytic me- 

 thod, by means of which we more completely attain to the knowledge of 

 ourselves. 



In order to conceive rightly the operations of the human intellect, and 

 explain the generation of the faculties of the soul, metaphysicians have 

 imagined a statue, into which they have infused a gradual animation, by 

 investing it, one by one, with our organs of sensation. Now, Nature has 

 realized in some sort this dream of philosophy. There are animals to 

 which she has entirely denied the organs of sight and hearing; in some, 

 taste and smell seem to have no separate existence from touch 5 in others, 

 she has exercised a sort of analysis on a system of parts which all concur 

 in one function. It is thus, that in some animals, divesting the organ of 

 hearing of the accessories allotted to collect, transmit, and modify the 

 rays of sound, she has reduced it to a simple cavity, filled with a gelati- 

 nous fluid, in which float the extremities of the acoustic nerve, alone fit- 

 ted to reeeive the impression of sound ; a fact which overthrows all the 

 hypotheses that had ascribed this sensation to other parts of the auditory 

 apparatus. 



Of all the physical sciences, Comparative Anatomy is that which fur- 

 nishes the most useful facts to physiology. Like physiology, it is concerned 

 with organized living beings : there is, therefore, no need of watching 

 against the false applications, so often made from the sciences, whose ob- 

 jects are matter inorganic and dead, or which study, in living beings only 

 the general properties of matter. Haller was so well aware of the utility 

 of introducing this science into physiology, that he has brought together 

 the greater part of the facts known in his time, on the anatomy of ani- 

 mals, at the head of each chapter of his immortal work. 



This general consideration of living and animated beings, so well adapt- 

 ed to unveiling the secret of our organization, has this further advantage, 

 that it enlarges the sphere of ideas of him who applies to it. Let him who 

 aspires to that largeness of conception, so requisite in medicine, where 

 facts are so multiplied and various, explanations so contradictory, and 

 rules of conduct so unfixed, cast a general glance on this great division 

 of organized beings, of which many, in their physical structure, so nearly 

 resemble man : he will see the sovereign Architect of the world distri- 

 buting to all, the element of life and activity, giving to some a less pow- 

 er of motion, to others more j so that, formed all on one model, they 

 seem only the infinitely varied, but gradual shades of the same form, if 

 forms have shades like colours; never passing abruptly from one to ano- 

 ther, but rising or falling by gentle and due degrees; covering the inter- 

 val that separates two different beings, with many species that serve as 

 a transition* from one to the other, and which present a continuous series 



* The conception is noble and interesting of a scale of being 1 , which, as was said by 

 C, Bonnet, connecting all the worlds, embracing all the spheres, should extend from 



