PHYSIOLOGY OF TREES. 253 



but a simple elongation of those components 

 which existed and composed it even in the bud. 

 Its parts are magnified, not multiplied. When 

 the growth receives a check, those parts of the 

 system which lie more immediately in the influ- 

 ential and central current of the sap rising from 

 the roots, will receive a stronger impulse than 

 those on the exterior, which are further removed 

 from it ; consequently, the flowers which are 

 generally, though not universally, seated on the 

 pith, receive the whole impetus of the subdued 

 vigour, and hence burst forth into view. 



Many other examples might be brought to 

 prove that the organi sable property of the sap 

 is not sound philosophy. The very arguments 

 brought forward in support of it are at least 

 ill chosen. It has been compared to the agency 

 of the blood of animals repairing a wound, or 

 filling up a separated part of a muscle of a living 

 body ; and to the formation of the chicken from 

 the homogeneous fluids of an egg ! But the 

 cases are quite dissimilar : In the first, the blood 

 only assists by enlargement and elongation of the 



