76 LETTERS TO BROTHER JOHN. 



onward ; and so on. All these contractions could 

 not, of course, be executed, if it were not for the 

 property of contractility that is, the ability to 

 contract. 



Now, all the motions of the different parts of the 

 body, without and within, are performed by these 

 contractions, and by virtue of this contractility. It 

 is the main-spring of the watch it is the chief wheel 

 in the machine it is the principal beam, the main 

 prop, of the building : by it we gather our food 

 by it we eat it by it we swallow it by it the 

 stomach sends it on to the bowels: from the 

 bowels it is carried to the heart by it ; and by it, 

 having become blood, it is circulated through the 

 body, for whose nourishment it is destined. Every 

 time your watch ticks, they say, one human being 

 is born, and one perishes, in some part or other 

 of the world. But in the human microcosm, 

 in that little insignificant world called "man," 

 every time his watch ticks there are millions of 

 molecules of the old body dissolved and carried 

 away, and their places supplied by as many mil- 

 lions of new : and all this mainly depends upon 

 this important property of contractility. When- 

 ever, therefore, I use the term contractility, you 

 will know that I mean that power by virtue of 



