233 



comes still more so when we observe that mankind and most animals 

 draw upon those parts of the plants for their nourishment, which we 

 usually consider to be the peculiar organs of reproduction : I mean 

 the seeds." — p. 63. 



After reverting to the power possessed by the individual cell of 

 forming new cells in its interior, and thus of propagating itself, the 

 author proceeds — 



" Now the newly-formed cells have also this peculiarity, they grow 

 and arrange themselves conformably to the cell in which they origi- 

 nate. Thus is the power given to all plants to develop new plants 

 out of any of their cells, when these come to be placed in favourable 

 circumstances, and by this power is explained the facility with which 

 almost all plants may be multiplied." — p. 65. 



To this power is referrible the production of buds upon various 

 parts of certain leaves, whether separated from, or while remaining 

 attached to the stem ; upon stems, in the axillae of the leaves ; and 

 other irregular modes of propagation : and equally referrible to it is 

 the regular mode by the production of the reproductive bodies known 

 as spores and seeds; which may be explained by the fact that — 



" Every plant produces within itself a definite number of single, 

 free, unconnected cells, which at a certain epoch spontaneously sepa- 

 rate from the plant. It is the peculiar character of those plants 

 which have true leaves, to produce these cells only in the interior of 

 the leaves, which at the same time often assume a very different form, 

 as for instance, in the stamens. Another condition is also worthy of 

 remark. Only in the very lowest plants, flowering wholly under wa- 

 ter, is the propagative cell naked ; in all others it is invested with a 

 peculiar substance, which has not yet been chemically examined, but 

 is mostly yellow and very indestructible. * * * Now these 

 cells are especially destined to the reproductive function, since from 

 every one of them is a new plant developed. An essential distinction, 

 however, occurs in this development ; one, indeed, recognized at an 

 early period, and so exclusively regarded, that the higher agreement 

 was altogether overlooked." — p. 69. 



In one mode of the development of these reproductive cells, that 

 which obtains in all the plants comprehended by Linnaeus in his 

 class Cryptogamia, they are at once scattered upon the earth, or in 

 the water, wherever the new plants are to grow. And then, 



" Either the whole cell is gradually transformed into a new plant, 

 new cells originating in it and taking its place, in these others, and 

 so on, which is the case in the Algae, Fungi, Lichens, and part of the 



