lect. ix] Modern Doctrines of Respiration. 225 



" remain not only suited for its perpetual circuit but also fitted 

 " for the due separation during that very circuit of the matters 

 " which have to be discharged from its midst." 



He insisted that two things have to be borne in mind in 

 relation to this " transpulsion through the soft porous tissues. 

 " The first, is the business of the vital tonic movement, which 

 " takes place and is developed in an independent manner, 

 u quite apart from our will and consciousness. By means of 

 " this the porous structures at one time being more constricted 

 " and compact, admit the blood more sparingly, and at another 

 " time being relaxed, give place to a readier and fuller passage." 

 This idea of the varying tonicity, of the varying tonic move- 

 ment, of the tissues was made by Stahl the corner-stone of 

 much of his pathology, and exerted a powerful influence over 

 medical thought for many years. 



The second thing on which Stahl insisted as a result of the 

 1 transpulsion ' is the warming of the blood. " The second point 

 " to be noticed is the heating of the blood under, nay rather, on 

 "account of this same movement of the circulation at once 

 " pulsatory and tonic, and of the special intensity of each of 

 "these two kinds of movement." The heating he says is 

 simply the mechanical effect of the friction developed during 

 the passage. " Here again we ought to bear in mind the 

 "purely mechanical nature of the whole action. That is to 

 " say, this heating does not depend on any foreign particular 

 " kind of matter (except alone the special chemical constitution 

 " of the blood itself), but solely and simply on the movement 

 "and on its greater or less intensity, the variations of which 

 "are dependent on the one hand on the impetus itself of the 

 " impulse, and on the other hand on the tonic rigidity of the 

 " tissues according as these are constricted or relaxed." 



Stahl thus deliberately rejects the view that the heat of 

 the blood and so of the body is due to chemical action ; he 

 regards it as solely and simply a mechanical effect. And this 

 conception of the origin of animal heat determined his view of 

 the function of breathing. According to him, the purpose of 

 the movements of the chest and of the lungs is to regulate 

 and facilitate the passage of the blood through the pulmonary 



F. L. 15 



