VEGETABLE PHYSIOLOGY. 



Fig. 3. 



And Fig. 4, compressed into dense plates, as found 

 in the medullary rays, and other parts of the stem, 

 flowers, and fruit. 



Fig. 4. 



The cellular body appears to have no determinate 

 limits, on which account it has been supposed to be 

 self-productive : it continues to increase and pro- 

 trude in every direction, if any vacancy is to be 

 filled up, or any part of the organisation to be com- 

 pleted. The organs are all formed of it, and it is 

 the material that unites them together. 



The exterior of a cellular body, when exposed to 

 the air, is always condensed into cuticle or bark ; and 

 from this effect, viz. the hardening action of the sun 

 and air, we invariably see it, in the act of expansion, 

 descending with more rapidity than increasing in any 

 other direction. 



This circumstance is exemplified by the upper side 





