PRELIMINARY DISCOURSES. 



that "seeds must die before they can come up," is a vulgar error. 

 Seeds that die, never "come up." The error probably originated 

 from observing the condition of the albumen, in seeds of the cerealia, 

 or edible grains, at the period of germination. The efficient cause, 

 or intimate nature, of growth, we do not, of course, pretend to 

 understand. Such knowledge is now and perhaps will remain 

 beyond the reach of finite beings ; but the physical agents concerned 

 their operations and results and the laws which regulate them 

 the curious observer can both perceive and comprehend, to a very 

 satisfactory extent. The solid portion of Plants is made up, mainly, 

 of an infinity of slender fibres, and delicate membranes forming 

 tubes, and cells, for conveying and containing fluids ; and the 

 physical process of growth consists in the extension and multiplica- 

 tion of those tubes and cells. When the fibrous portion (which 

 results from elongated cells,) predominates, the plant becomes firm 

 and woody; and when the strictly cellular structure prevails 

 whether in stem, leaves, or fruit the product is fleshy, tender and 

 succulent. The same wise Power which endowed plants with 

 vitality, and the capacity for growth, or development, has also 

 established laws to control that development, whereby each plant 

 assumes a determinate form and character; which, although liable 

 to variation in the subordinate features (as in texture, size, color, 

 or other trait of secondary importance in the vegetable economy), 

 are nevertheless essentially perpetuated in the species. It is this 

 fixedness of character which enables the Botanist to recognize, and 

 distinguish, the various kinds, and, in classifying them, to ar- 

 range each with its kindred. 



But our present business is with the changes or modifications, 

 which successively take place, at successive stages of development, in 

 the foliaceous appendages of the same plant. Naturalists have 

 observed, that in the stems and branches of plants, there are small 

 portions, found at certain intervals, which are more firm and dense 

 than the other parts. These firmer portions are termed knots, or 

 nodes, and the intervening spaces are called internodes. These 

 nodes exist, under some form, and in greater or less abundance, in 

 all stems: sometimes being crowded together, and condensed at 

 certain points of the stem, so as to form complete, and often solid" 

 rings (or joints, as they have been rather incorrectly termed) ; at 

 others, they are much divided, and appear in scattered points on 

 the circumference, in which latter case, they are usually disposed 

 in an ascending spiral line. They seem to have an intimate con- 

 nection with the formation of all leaves, and buds, and are, at least, 



