118 



PHYSIOLOGICAL VIEWS. 



Fi2;.120 



Pig. 120, at A, represents a section of the stipe or stem of a palm- 

 tree ; at 7?, is the same magnified ; a, 6, shows a part of the stipe in 

 which the woody fibres are most dense and hard ; b, c, shows the 

 fibres less numerous, less compact, and less hard ; c, d, includes the 

 woody fibres, tender and scattered ; the orifices of tubes which have 

 disappeared are seen at c, a. In the part c, d, the cellular tissue oc- 

 cupies a greater space than at c, 6, and much more than at b, a, 

 where the woody fibre, or vascular texture, predominates. The 

 fibres at e, are of new formation 5 at/, they are older, and at g, still 

 more ancient ; thus the development of the wood in this plant pro- 

 ceeds inversely to that of dicotyledonous plants. 



Endogenous plants continue to increase in height, long after they 

 cease to grow in diameter ; the stem is gradually extended upward 

 by new terminal shoots, which are formed annually. 



The epidermis is formed of the foot-stalks of leaves, which an- 

 nually sprout from the rim of a new layer of wood; the leaves fall 

 ingin autumn, their foot-stalks become indurated, and remain upon 

 the outer surface of the plant. 



We have now taken a brief view of the most important facts and 

 principles which constitute the science of vegetable anatomy and 

 physiology. Although the vegetable structure is much less compli- 

 cated than the animal, there are many analogies between them ; and 

 many parts of the former have been named, and various phenomena 

 explained, by a reference to names and principles common to animal 

 anatomy and physiology. You cannot therefore expect, at the first 

 glance, to comprehend explanations which presuppose some know- 

 ledge of those intricate subjects. By attention to the vegetable struc- 

 ture, you will, doubtless, be induced to think more upon the wonderful 

 mechanism of your own material frames; upon the analogy, and 

 yet infinite difference, between yourselves and the lilies of the field. 



In considering these things, we are led to exclaim, in the language 

 of the Psalmist, " Oh Lord, how manifold are thy works, in wisdom 

 hast thou made them all !" The human body is nourished by the 

 same elements as the grass which perisheth; the flowers have a 

 much more refined corporeal substance than you, but how much 

 more precious are you in the sidit of the Almighty ! 



Do you ask, why you are of more value "than the lilies of the 

 i.eld," or even than "many sparrows?" It is the very principle 



What is Fig. 120 designed to illustrate?— How is^ the Epidermis formed T —Jleflec- 

 uonson the analogies between the vegetable and animal substances. 



