NOVUM ORGANUM. 163 



the spirit does not find pores and passages for its escape, 

 and is therefore obliged to force out, and drive before it, 

 the tangible parts also, which consequently protrude ; 

 whence arises rust, and the like. The contraction of the 

 tangible parts, occasioned by the emission of part of the 

 spirit (whence arises desiccation), is rendered sensible by 

 the increased hardness of the substance, and still more by 

 the fissures, contractions, shrivelling, and folds of the bodies 

 thus produced. For the parts of wood split and contract, 

 skins become shrivelled, and not only that, but, if the spirit 

 be emitted suddenly by the heat of the fire, become so 

 hastily contracted as to twist and roll themselves up. 



On the contrary, when the spirit is retained, and yet ex 

 panded and excited by heat, or the like (which happens in 

 solid and tenacious bodies), then the bodies are softened, as 

 in hot iron ; or flow, as in metals ; or melt, as in gums, wax, 

 and the like. The contrary effects of heat, therefore (hard 

 ening some substances and melting others), are easily recon 

 ciled,* because the spirit is emitted in the former and 

 agitated and retained in the latter ; the latter action is that 

 of heat and the spirit, the former that of the tangible parts 

 themselves after the spirit s emission. 



But when the spirit is neither entirely retained nor 

 emitted, but only strives and exercises itself, within its 

 limits, and meets with tangible parts, which obey and readily 

 follow it wherever it leads them ; then follows the formation 

 of an organic body, and of limbs, and the other vital actions 

 of vegetables and plants. These are rendered sensible, 

 chiefly by diligent observation of the first beginnings, and 

 rudiments or effects of life in animalculae sprung from putre 

 faction, as in the eggs of ants, worms, mosses, frogs after 

 rain, &c. Both a mild heat and a pliant substance, how 

 ever, are necessary for the production of life, in order that 

 the spirit may neither hastily escape, nor be restrained by 

 the obstinacy of the parts, so as not to be able to bend and 

 model them like wax. 



Again, the difference of spirit which is important and of 

 effect in many points (as unconnected spirit, branching 

 spirit, branching and cellular spirit, the first of which is 



inanimate objects. His theory as to the generation of animals is deduced from 

 the erroneous notion of the possibility of spontaneous generation (as it was termed). 

 See the next paragraph but one. 



* Limus ut hie durescit, et haec ut cera liquescit 

 Uno eodemque igni. Virg. EC/, viii. 



