284 



ON THE NUTRITION OF 



where the one is in a small degree, the other makes 

 up for the deficiency, by being in itself more consi- 

 derable. The sum-total of retentive powers of mois- 

 ture thus possessed, may not be strictly equal in all, 

 but proportioned to the degree of adaptation of the 

 different substances to circumstances of external 

 condition. 



We are, therefore, to conceive, on the whole, that 

 there is in the interior of all such organs, a constant 

 dampness without any flowing liquidity ; and that 

 this dampness contributes to the transmission of all 

 nutritious impregnations ; in the same manner in 

 which we find, that the presence of moisture pro- 

 motes the evolution of those exhalations which an- 

 nounce to the sense of smell certain differences of 

 character in the properties of different animal -sub- 

 stances. The quantities of matter thus conveyed 

 must be more minute than those which pass in the 

 state of blood. But the transmission is constant ; 

 the assimilating functions of the nourished parts are 

 always active ; and we are not authorised to pro- 

 nounce on the maximum of the proportion which is 

 taken from the transmitted substance for the pur- 

 pose of assimilation. 



The structure, though thus open, must not be 

 conceived to be indeterminate. There are passages 

 of various qualities, through some of which the hali- 

 tus is conveyed more readily, and through others less. 

 These passages differ not only in width, but in the 



