NOVUM ORGANUM. 341 



modo et subjecto difFerant. Motus enim Assimilationis procedit 

 tanquam cum imperio et potestate ; jubet enim et cogit assimi- 

 latum in assimilantem verti et mutari. At Motus Excitationis 

 procedit tanquam arte et insinuatione et furtim ; et invitat 

 tantum, et disponit excitatum ad naturam excitantis. Etiam 

 Motus Assimilationis multiplicat et transformat corpora et sub- 

 stantias ; veluti, plus fit flammse, plus aeris, plus spiritus, plus 

 carnis. At in Motu Excitationis, multiplicantur et transeunt 

 virtutes tantum ; et plus fit calidij plus magnetici, plus putridi. 

 Eminet autem iste motus prascipue in calido et frigido. Neque 

 enim calor diffundit se in calefaciendo per communicationem 

 primi caloris ; sed tantum per Excitationem partium corporis 

 ad motum ilium qui est Forma Calidi ; de quo in Vindemi- 

 atione Prima de Natura Calidi diximus. Itaque longe tardius 

 et difficilius excitatur calor in lapide aut metallo quam in acre, 

 ob inhabilitatem et impromptitudinem corporum illorum ad 

 motum ilium ; ita ut verisimile sit posse esse interius versus 

 viscera terras materias quas calefieii prorsus respuant ; quia ob 

 condensation em major em spiritu illo destituuntur a quo Motus 

 iste Excitationis plerunque incipit. Similiter magnes induit 

 ferrum nova partium dispositione et motu conformi ; ipse autem 

 nihil ex virtute perdit. Similiter ferment um panis, et flos 

 cervisige, et coagulum lactis, et nonnulla ex venenis, excitant 

 et invitant motum in massa farinaria, aut cervisia, aut caseo, 

 aut corpore liumano, successivum et continuatum ; non tarn ex 

 vi excitantis quam ex praedispositione et facili cessione exci- 

 tati. 1 



Sit Motus Decimus Tertius, Motus Impressionis ; qui Motus 

 est etiam ex genere Motus Assimilationis, estque ex diffusivis 



1 The theory here proposed is nearly equivalent to the most recent views on the 

 same subject, as the following passage will sufficiently show. It is obvious that both 

 statements, however much of truth they may involve, are indefinite and unsatisfactory. 

 It is not said whether the new properties engendered depend upon new types of 

 motion or new arrangements, though the latter is probably Liebig's opinion. 



" All the phenomena of fermentation, when taken together, establish the correctness 

 of the principle long since recognised by Laplace and Berthollet, namely, that an 

 atom or molecule, put in motion by any power whatever, may communicate its own mo~ 

 tion to another atom in contact with it. 



" This is a dynamical law of the most general application, manifested everywhere 

 when the resistance or force opposing the motion, such as the vital principle, the force 

 of affinity, electricity, cohesion, &c., is not sufficiently powerful to arrest the motion 

 imparted. 



" This law has only recently been recognised as a cause of the alterations in forms 

 and properties which occur in our chemical combinations ; and its establishment is 

 the greatest and most enduring acquisition which chemical science has derived from 

 the study of fermentation."- Liebig's Letters on Chemistry, p. 209. 



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