6 GOETHE ON THE METAMORPHOSIS OF PLANTS. 
the more or less modified fluids which they draw from the stem; it is to 
the light and air that they are indebted for their increased perfection in 
form, and for the delicacy of their tissue. The cotyledons which are 
produced beneath the covering of the seed, are charged as it were with 
nothing but a crude kind of sap, are scarcely at all, or but rudely or- 
ganized, and undefined; in the same way the leaves of plants which 
grow under water are more rudely organized than others which ave ex- 
posed to the air; nay, even the same kind of plant will develope 
smoother and more imperfectly formed leaves when growing in low, 
damp situations, than it will if transplanted to a higher region; where, 
on the contrary, the leaves will be rough, hairy, and more delicately 
finished. 
25. So also the anastomosis of the vessels which arise from the 
ribs, and continually tend to inoseulate at their extremities, (by which 
also the cuticle (Blatthdutchen) of the leaf is formed) ; is, if not en- 
tirely produced by subtile gases, at least greatly accelerated by them.* 
The reason why the leaves of many plants which grow under water 
are capillaceous, is owing to an imperfect anastomosis. This is clearly 
shown in Ranunculus aquatilis, where the aquatic leaves consist of 
eapillaceous veins, whilst in the aerial leaves the anastomosis is com- 
plete, and a connected surface is formed.+ 
` 96. Experiments have shown that leaves absorb different kinds of 
gases, and combine them with their sap ; thesc juices are returned in a 
more refined state into the stem, and thereby eminently promote the 
formation of the adjacent buds. Gases disengaged from the leaves and 
hollow. stems of different. plants have been amalysed, and afford the 
most convincing evidence of this.f 
27. We observe in many plants that one node arises from another. 
In the jointed stems of the cereals, grasses and reeds, this is obvious ; 
HA What share subtile gases can have in the formation of the cuticle, and in the 
Inosculation of the veins, is by no means obvious. > 
* The filamentous condition of the leaves of some water-plants is rather due to 
the scanty dev 
— elopment of the cellular portions of the leaf ( parenchynfa) than to the 
Moda ect inosculation of the fibro-vascular bundles. The leaf of the Lattice-plant of 
ie Menu an Ouvirandra fenestralis, affords a remarkable illustration of the defi- 
bet ey i nehyma ; here the inosculation of the veins is perfect, but as the spaces 
non tem are not filled up with cellular tissue, the whole leaf has the appearance 
— ace also not inaptly be compared with the so-called skeleton leaves 
f One of the most im : : — — 
diui in hen Bs Mee me recent memoirs on this subject is that of Boussin. 
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