IRRITABILITY, AND MUSCULAR POWER. 103 



first is, that admitting the absolute necessity of the health or perfection o' 

 every separate part to the health or perfection of the whole, we are still as 

 much in the dark as ever in respect to the principle by which this harmoni- 

 ous machine has been developed, and is kept in perpetual play. The second 

 objection, by which, indeed, it was vigorously attacked by the Epicureans, 

 and at length completely driven from the field, is derived from observing that 

 the health or well-being of the general system does not depend upon that of 

 its collective organs ; and that some parts are of far more consequence to it 

 than others. Thus the mind, observes Lucretius, in his able refutation of 

 this hypothesis, may be diseased, while the body remains unaffected ; or the 

 body, on the contrary, may lose some of its own organs, while the mind, or 

 even the general health of the body itself, continues perfect. 



The abbe Polignac, who, consistently with the Cartesian system, makes a 

 very proper distinction between the principle of the mind or soul, and that of 

 the life, enters readily into the hypothesis of Aristoxenus in regard to the 

 latter power, though he thinks it inapplicable to the former: and Leibnitz 

 appears to have availed himself of it as a means of accounting for the union 

 between the soul and body in his celebrated system, which he seems to have 

 named, from the theory before us, the system of PRE-ESTABLISHED HARMONY. 

 By a writer of the present day, however, M. Lusac, the doctrine of Aristoxe- 

 nus seems to have been resuscitated in its fullest scope, and even to have 

 been carried to a much wider latitude than its inventor had ever intended : 

 for the theory of M. Lusac affects to regard, not only the frame of man and 

 other animals, but the vast frame of the universe, as a sort of musical organ 

 or instrument ; the concordant and accumulated action of whose different 

 parts or agents he denominates, like Aristoxenus, harmony. " Concerts of 

 music," says he, " afford a clear example : you perceive harmony in music 

 when different tones, obtained by the touch of various instruments, excite 

 one general sound, a compound of the whole." "This observation he applies 

 to the grand operations of nature, the irregularities of which, resulting from 

 inundations, earthquakes, volcanoes, tempests, and similar evils, this philoso- 

 pher considers as the dissonances occasionally introduced into music to 

 heighten the harmony of the entire system. With respect to the harmony 

 of the human frame, individually contemplated, or the concordant action of 

 the different parts of the body, he observes, " It may be said, that of this 

 principle I have merely a confused notion ; and I admit it, if the assertion 

 imply that I have neither a perfect nor a distinct, nor an entire comprehen- 

 sion of what produces this harmony in what it consists, or how it acts. I 

 know not what produces the harmony of various instruments heard simulta- 

 neously; but I can accurately distinguish the sounds which are occasioned 

 when musicians are tuning, from those which are produced when, being com- 

 pletely in tune, and every one uniting in the piece, the separate parts are 

 executed with precision. When I hear an harmonious sound, whatever be 

 its nature, I can distinguish the harmony, though incapable of investigating 

 its cause."* 



I shall only observe, farther, that in the doctrine of Mr. (now Sir Humphry) 

 Davy, which holds life itself as a perpetual series of corpuscular changes, 

 and the substrate, or living body, as the being in which these changes take 

 place, we cannot but observe a leaning towards the same system ; and we 

 shall have occasion, in a subsequent lecture, to* notice one or two others of 

 equally modern date that touch closely upon it in a few points.! 



Let us pass on, then, to a consideration of the second hypothesis I have 

 noticed, and which consists in regarding the BLOOD ITSELF AS THE PRINCIPLE 

 OF LIFE. This opinion lays claim to a still higher antiquity than the pre- 

 ceding ; and, in a general view of the question, is far better founded. It has 

 the fullest support of the Mosaic writings, which expressly appeal to the doc- 

 trine, that " the life of all flesh is the blood thereof,";): as a basis for the culi- 



* Du Droit Naturel, Civil, ct Politique, torn. i. 154. t Series HI. Lecture v. 



t Levit xvii. 14 



