20 
ORGANOGRAPHY. 
BOOK I. 
body, which, to judge from its shadow, represents a thick 
ring or a thick-sided hollow spherule : there is generally but 
one such spherule to each Cytoblast, but occasionally there 
are two or even three. The spherule varies in size from 
half the diameter of the Cytoblast to a point too small to be 
measured ; and Dr. Schleiden has ascertained that this 
minute body is formed earlier than the Cytoblast itself. It 
is sometimes darker, sometimes clearer than the rest of the 
Cytoblast; and is usually of a firmer consistence, remaining 
well defined when the latter is crushed by pressure into 
amorphous mucus. 
If the gum which is found in the youngest albumen of a 
plant be examined, it will be found turbid with molecules of 
extreme minuteness. Of these some acquire a larger size and 
a more definite outline than others, and by degrees Cytoblasts 
appear, which seem to be a granular coagulation round each 
molecule. As soon as the Cytoblast has attained its full size, 
there appears upon it a fine transparent vesicle; this is a 
young cell, wdiich at first represents a very flat segment of a 
sphere whose flat side is formed of the Cytoblast and convex 
side of the young vesicle, which is fixed upon it like the half 
of an hour-glass {wie ein Uhrglas auf einer Ulir). The space 
lying between the convexity of the vesicle and the Cytoblast 
is as clear and transparent as water, and is apparently filled 
with an aqueous fluid. If these young cells are isolated, we 
may, by shaking the field of the microscope, wash the mucous 
molecules almost clean; but they cannot be long observed, 
because they dissolve in distilled water in a few minutes, and 
leave nothing but the Cytoblast behind. The vesicles con- 
tinue to swell out, and their lining becomes formed of jelly, 
with the exception of the Cytoblast, which soon becomes a 
part of their wall : the cell keeps increasing in size, till at last 
the Cytoblast is only a minute body imbedded in the side of 
the cavity, or sometimes loose in the cavity. It is, however, 
in time absorbed, and it is only after its absorption has oc- 
curred that, as Schleiden believes, the process of depositing 
secondary layers begins. The Cytoblast appears, how^ever, 
sometimes to have a permanent existence, as in the pollen of 
Larix europaea, and in those hairs in which a circulation of 
