Introduction to cryptogamic botany / by M.J. Berkeley.

Date:
1857
Catalogue details

Licence: Public Domain Mark

Credit: Introduction to cryptogamic botany / by M.J. Berkeley. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    mentioned mcay be examined profitaLly in Phsenogams, but always with more difficulty, and seldom with such precision or with such satisfaction and conviction to the observer, and there is one point which must always be borne in mind, that the objects in question grow and are developed under his eyes, if he possesses proper powers of manipulation, which will scarcely ever be the case with Phaenogams, if the parts be freed ever so neatly from the surrounding tissues.* Nay, the examination of the developement of cells in such genera as Hobmatococcua and Glceocapsa (Fig. 10) will help even the Zoologist, for no- thing can be more close than the mode of development in these, and of the vitellus in the eggs of certain MoUusca (Figs. J1,12). rig. 11. Eggs of Acteon viridis in different stages. a. Egg, showing the vitellus still simple. 6. Egg, with four celled vitelJus. c. The vitellus divided into two. d. Ditto into four. From Vogt Recherches sur I'Embryogenie des MoUusques Gasteropodes, Ann. d. Sc. Nat., s6r. iii. vol. 6, p. 1. The bodies, indeed, which are so much alike, or in other words are homologous, identical, that is, in structure and genesis, though not in function, may not always be of equal * Most eminent vegetable Physiologists have been more or less Cryptogamists. One of the earliest studies of Mr. R. Brown was Schmidel's loones, a work which anticipates many modern observations, as the spiral structure of the threads in Trichia, and the motion of the S];ermatozoids in Jungermannia, and one of the best memoirs on the development of the embryo in vegetables, is that of Tulasne.