142 Van Helmont and the Rise [lect. 



So far I have dwelt upon van Helmont's work on what we 

 may call its rational side. What I have briefly described 

 constitutes a general exposition of the main facts of chemical 

 physiology, as van Helmont conceived them, and, as we have 

 seen, many of his conclusions were based on careful observations 

 and indeed on experiment. That exposition exerted a great 

 influence on investigators coming after him. In the first place 

 it shewed that many of the problems of the living body were 

 chemical problems to be solved by chemical knowledge, not 

 problems of a mechanical nature only, not problems to be 

 solved by the experimental verification of a suggestion offered 

 by anatomical arrangements. In the second place it drew the 

 attention of inquirers to the fact, which experience has shewn 

 to be an undoubted fact, that a large number of the processes- 

 taking place in the living body are more or less akin to the 

 process by which yeast produces alcohol, as in wine making or 

 brewing, and therefore may be spoken of as fermentations. 

 This idea of the fermentative nature of the changes taking 

 place in the living body was as we have said an old one, it had 

 been preached by Paracelsus; but its definite introduction into 

 physiological thought is due to van Helmont. The authors 

 coming afterwards who dwelt on the subject all acknowledge 

 their indebtedness to him. In the third place his discovery of 

 carbonic acid gas, and of other gases, for he recognised that all 

 gas was not alike, that some gas for instance was inflammable, 

 was a chemical discovery of prime importance, though the 

 value of the discovery did not become apparent until after the 

 lapse of many years. 



But to judge by his writings van Helmont was at heart 

 more pleased with his Bias than with his Gas. In the ex- 

 position of which I have given an account there are repeated 

 interpositions, which I have omitted, numerous references to the 

 action of this or that bias or archaeus. And any attempt to 

 picture van Helmont's mind would be incomplete without at 

 least some few words about his views as to the relations of the 

 archaeus, and so of the phenomena of the body, to what he calls 

 the sensitive and motive soul, the anima sensitiva motivaque. 



" This sensitive soul belongs to man alone ; for speaking 



