PHYSIOLOGY OF ORGANIC LIFE. 123 



to flow through ; those parts of the whole would 

 flow through, which possess quantity with 

 color and figure; quality without aptitude; 

 that would act upon the organs instead of re- 

 taining the fitness alone to be acted upon by 

 them. To prevent this evil, a gradual diminu- 

 tion in the size of the secretory vessels exists, 

 in order that the fluid which they exhale may 

 answer, in the best possible manner, the end for 

 which it is designed; this fluid is, therefore, 

 tasteless and inodorous, colorless and tenuous. 

 If blood possessed any power of action with- 

 in itself, it would resist the action of the organs 

 to which it was applied ; it would act upon 

 them, instead of being changed and converted 

 l)y them ; it is moved without the power of 

 moving itself; it is propelled without resisting, 

 and follows the impulse it receives, from the 

 power of the vessels in which it is contained ; 

 not according to the principles by which fluids 

 are moved in hydraulic machines, but by powers 

 altogether different from them. The relation 

 which exists between the blood and the vessel 

 in which it is contained, is precisely the same, 

 in kind, as subsists between the glands on which 

 it is deposited, and the blood : while the power 

 of the one is similar to the figures engraven 

 on a seal, the other resembles the softened 

 and adapted wax which is to receive the im- 

 pression. It is by the energy of the former, and 



