190 NOVUM ORGANUM. 



nature. Nor does this assimilation, or simple generation, 

 take place in animated bodies only, but the inanimate also 

 participate in the same property (as we have observed of 

 flame and air), and that languid spirit, which is contained 

 in every tangible animated substance, is perpetually working 

 upon the coarser parts, and converting them into spirit, 

 which afterwards is exhaled, whence ensues a diminution 

 of weight, and a desiccation of which we have spoken 

 elsewhere.* Nor should we, in speaking of assimilation, 

 neglect to mention the accretion which is usually distin 

 guished from aliment, and which is observed when mud 

 grows into a mass between stones, and is converted into a 

 stony substance, and the scaly substance round the teeth 

 is converted into one no less hard than the teeth them 

 selves ; for we are of opinion that there exists in all bodies 

 a desire of assimilation, as well as of uniting with homo 

 geneous masses. Each of these powers, however, is confined, 

 although in different manners, and should be diligently 

 investigated, because they are connected with the revival 

 of old age. Lastly, it is worthy of observation, that in the 

 nine preceding motions, bodies appear to aim at the mere 

 preservation of their nature, whilst in this they attempt its 

 propagation. 



Let the twelfth motion be that of excitement, which 

 appears to be a species of the last, and is sometimes men 

 tioned by us under that name. It is, like that, a diffusive, 

 communicative, transitive, and multiplying motion; and 

 they agree remarkably in their effect, although they differ 

 in their mode of action, and in their subject matter. The 

 former proceeds imperiously, and with authority ; it orders 

 and compels the assimilated to be converted and changed 

 into the assimilating body. The latter proceeds by art, 

 insinuation, and stealth, inviting and disposing the excited 

 towards the nature of the exciting body. The former both 

 multiplies and transforms bodies and substances ; thus a 

 greater quantity of flame, air, spirit, and flesh is formed ; 

 but in the latter, the powers only are multiplied and changed, 

 and heat, the magnetic power, and putrefaction, in the 

 above instances, are increased. Heat does not diffuse itself 

 when heating other bodies by any communication of the 

 original heat, but only by exciting the parts of the heated 

 body to that motion which is the form of heat, and of which 

 we spoke in the first vintage of the nature of heat. Heat, 



See the Citing Instances, Aphorism 40. 



