108 DEVELOPMENT OF COMPOUND 



are at first completely astounded. Nature herself by this 

 means teaches us her own processes, and this too by such 

 evidence as none can gainsay or deny. 



The reproductive always exhausts the vegetative force. 

 All physiologists will concede me this ground unhesitatingly. 

 It is well known that this is one of those grand laws which 

 govern every form of organized matter. Animals and plants 

 must first vegetate before they can reproduce ; and reproduc- 

 tion in both always checks growth and exhausts the vital 

 powers of the organism. Hence leaves take a simpler form 

 in the neighborhood of the flower. They are not so highly 

 organized, because their development is gradually arrested, 

 and the vegetative force diminishes in intensity as the repro- 

 ductive force becomes manifest. There is a mutual antago- 

 nism between these two forces. There can be no doubt as to 

 the influence exercised by this law in modifying the foliage 

 of plants. It is only necessary to compare the leaves in the 

 neighborhood of the flower with those at some distance from 

 it, in the vegetative region, to see the gradual simplification 

 of leaf- structure, as we pass from the vegetative to the floral 

 region. 



Now, such investigations are exceedingly instructive ; for 

 if we carefully examine the leaves of plants at different points 

 of height along the stem, it will be seen that they present 

 notable differences of form, and that the most intimate ties 

 of relationship subsist between lobes, crenatures, teeth, etc. 

 Generally speaking, the leaves attached toward the inferior 

 portion of the stem are cut into teeth or lobes more or less 

 numerous, and are connected with the stem by a petiole or 

 stalk ; but in proportion as they are situated near the flower, 

 they become smaller, lose their stalk or support, and become 

 sessile, the teeth, lobes and other irregularities disappear from 

 the margin of their lamina, which becomes entire, and they 

 gradually approach the floral leaves in form, until finally they 

 cannot be distinguished from them except by their position 

 around the stem. The gradual disappearance of the serratures 

 from the margin of the leaves in proportion to their proximity 

 to the flowers, may be seen to advantage in the different 



