108 FOURTH REPORT — 1834. 



arte, electione et providentiS institui, quam animse rationalis 

 mentisve actiones ; idque etiam in homine perfectissimo." 



A peculiar matter is necessary for the manifestation of vital 

 phsenomena : this matter is called organic. It is not the cause 

 of life, but rather is its act; a production by means of the assi- 

 milative process, for the exemplification of the allotted faculties. 

 The faculty is imperfectly manifested if the organ be imper- 

 fectly formed : the organ and its energy both vary with varia- 

 tions in the nutritive process*. 



Hence those subordinate expressions of vital force, called tie?'- 

 voits power, force of secretion, tkc, cannot be considered as di- 

 stinct and independent powers. They are produced, or evidenced, 

 with their organs, by the force of assimilation, and are main- 

 tained by the same. They depend upon it for their manifesta- 

 tion and their due support f. 



Vital power imparted to organic matter (which is itself the 

 product of the living power of the parents), and exemplifying 

 its faculties by means of the organs which it has developed 

 through the force of nutrition, seems to be the last step to which 

 observation and induction has hitherto led us. The induction is 

 verified by observation. If the assimilative process be altered in 

 any organ, the expression of excitability and of vital reaction 

 peculiar to that organ is altered in the same degree. 



There are then in living bodies as many species of excitability 

 and as many modes of reaction as there are tissues. Every one 

 of these has its own mode of both, which is called into action 

 by its own appropriate stimuli. " Whatever these stimuli may 

 be, — whether external, as air, light, warmth, food ; or internal 

 stimuli, the blood, nervous influence, the secreted humours, — 

 each organ reacts in its own peculiar manner ; a manner which 

 supposes a peculiar organic power imparted to it in the act of 

 its formation by the process of nutrition, and sustained by the 

 same J." " The stimulus maybe that of a chemical, or mechani- 

 cal, or organic substance ; the reaction, however, is always vital, 

 and indicates the existence of an organic force, of which it is the 

 effect. The physical properties of the one are in some sort in a 

 constant conflict with the vital properties of the other, and living 

 bodies only preserve their character of life so long as they are 

 able to resist the physical impression. When it is said that or- 

 ganic movements are occasioned by incitations, we do not admit 



• Tiedeniann, Pliysiulogie. f Tiedemann. 



J Tiedemann, Pliysiulogie, vol. ii. In this excellent work, worthy of the 

 great name of its author, the theory, of which I have given this hasty notice, 

 is fully developed. 



