90 LETTERS TO BROTHER JOHN. 



tractions are also performed in virtue of the con- 

 tractile power, or contractility, it is again manifest 

 that the energy with which these internal motions 

 are performed (and by which nutrition is effected) 

 will be also in proportion to the energy of the con- 

 tractile power : and as health consists in the due 

 energy (as we have before seen) with which these 

 motions or actions are effected, it follows, clearly 

 and logically, that a high degree of contractile 

 power is synonymous with a high degree of health ; 

 and that a low degree of contractile power is synony- 

 mous with feeble health. 



Having premised the above short paragraph, I 

 now proceed to mention to you the first important 

 law to which contractility is subject, viz. EVANES- 

 CENCE. Contractility can only exist in perfection 

 in recently-organized matter. No sooner has a 

 molecule of matter become organized and assimi- 

 lated to the living matter, than its contractility 

 begins to fade to evaporate, as it were, like breath 

 which has been breathed upon a highly-polished 

 surface, such as steel, or looking--glass. Indeed, 

 it seems to be the evanescent nature of contracti- 

 lity which has given occasion to that particular 

 contrivance by which life is supported; viz. by 

 constant organization and disorganization ; that is, 



