1864. | The Microscope. 557 
branch of Natural History from which the illustrations are drawn ; 
indeed, as far as it goes, it is admirably written, and we feel sure that 
every large-minded microscopical writer or observer will agree with 
us, When we pronounce Dr. Griffith’s little work the best of the kind 
extant. Its chief merit consists in its truly educational character, 
which raises it above many of those brochures whose sole object seems 
to be to afford amusement for the hour; but this feature does not by 
any means render it the less interesting and attractive. 
If we take, for example, Chapters III. and IV., we find that the 
beginner is taught by means of practical illustrations, not alone the 
character of “vegetable elements and tissues,” but of the organs and 
functions of plants; and if he takes care to seek out the objects 
recommended for his observation, he cannot fail to become acquainted 
with the nature and functions of leaves, stems, roots, flowers and seeds, 
and with the leading phenomena of fertilization. But our readers 
may be disposed to think that, in order to instil into the mind of the 
tyro such an amount of general information, the author must have 
recourse to technical language, and must avail himself of illustrations 
difficult of access to the student. By no means; in all such matters 
the author has smoothed the way for the uninitiated, the burthen of 
whose labours he has to a great extent borne himself, employing the 
clearest language, explaining every technicality, and, above all (and 
this is a great merit in the little work), availing himself, not of the old 
stock subjects for illustration, but of substances well known to the least 
informed, and readily procurable by every one. 
Here, for example, are the teachings of a cell from the pulp of an 
apple :— 
*Cell-Contents.—In most cells, especially when young, a minute, 
rounded, colourless body may be seen, either in the middle or on one side, 
called the nucleus. This is very distinct in a cell of the pulp of an apple 
(Pl. 1, Fig. 2b): and within this nucleus is often to be seen another smaller 
body, frequently appearing as a mere dot, called the nucleolus. 
‘The nucleus is imbedded in a soft substance, which fills up the entire 
cell (Pl. 1, Fig. 20); this is the protoplasm (rgcdros, first, rAdca, forma- 
tive substance). As it is very transparent it is readily overlooked ; but it 
may usually be shown distinctly by adding a little glycerine to the edge of 
the cover with a glass rod, when it contracts and separates from the cell- 
walls, as in the Jower cell of Fig. 2. The protoplasm in some cells is semi- 
solid, and of uniform consistence, while in others it is liquid in the centre, 
the outer portion being somewhat firmer, and immediately in contact with 
the cell-wall. In the latter case it forms an inner cell to the cell-wall, and 
is called the primordial utricle. The terms ‘‘ protoplasm ” and “ primordial 
utricle ” are, however, used by some authors synonymously. 
‘The protoplasm is the essential portion of the cell, and it forms or 
secretes the cell-wall upon its outer surface in the process of formation of 
the cell, considered as a whole. It is also of different chemical composi- 
tion, from the cell-wall being allied in this respect to animal matter.’ 
Thus simply, and with the aid of the cell from the pulp of an 
apple, does the author convey to his uninformed readers the chief facts 
in regard to one of the most difficult questions in vegetable physiology ; 
and as he has drawn upon the apple for his illustration in this instance, 
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