m] of the New Physics. 75 



"in the muscles, it is evident that the substance or the 

 "influence which the nerves transmit is not taken by itself 

 " alone sufficient to bring about that inflation. It is necessary, 

 "therefore, that something else must be added, something 

 " which is to be found in the muscles themselves; or that in 

 "the muscles there is some adequate disposition of material 

 "so that on the arrival of the influence transmitted by the 

 "nerves there takes place something like a fermentation or 

 "ebullition, by which the sudden inflation of the muscle is 

 "brought about. That such an action is possible is rendered 

 " clear by innumerable experiments which are continually being 

 " made in chemical elaborations as when spirits of vitriol are 

 "poured on oil of tartar; indeed all acid spirits when mixed 

 " with fixed salts, at once boil up with a sudden fermentation. 

 " In like manner therefore, we may suppose that there takes place 

 " in a muscle a somewhat similar mixing from which a sudden 

 " fermentation and ebullition results, with the mass of which 

 "the porosities of the muscle are filled up and enlarged, thus 

 " bringing about the turgescence and the inflation." 



I must not dwell any longer on Borelli's views concerning 

 muscular contraction. I shall have to take them up again in 

 connection with the labours of other men on the same subject. 

 I have said enough to shew how great and rapid an advance 

 in our knowledge of these matters had been brought about by 

 the new physical learning. Working on mechanical mathe- 

 matical lines, and almost on these alone, for it is only at the 

 end that he calls into his aid some of the chemical ideas which 

 were beginning to stir men's minds, and his no less than others, 

 but which were as yet far behind the already current physical 

 ideas, Borelli was able to approach very near the conception 

 which was not to be laid hold of for a century or more, the 

 conception of the irritability of muscle maintained by nutritive 

 processes, and of the calling that irritability into play by the 

 advent of nervous impulses. 



Borelli had also much to say concerning the internal 

 movements of the body, movements other than those carried 

 out by the skeletal muscles. He dwells at length on the 

 movements of the heart and on the circulation. 



