THE LOWEST FORMS OF LIFE. 
57 
to explain liow and wherefore, I may add, that upon this 
principle, too, the substances that we eat and drink are 
ultimately distributed through our bodies ; for it is by means 
of simple cells that they are taken up and conveyed into the 
blood : so you see, that small and apparently insignificant 
organisms often perform very important offices. 
“ So much for the mode in which the cell is nourished : now 
a word as to its growth and reproduction, and then, I 
think, you will have made sufficient progress in vegetable 
physiology to enable you at least to understand the history of 
Volvox globed or. 
“ Immediately within the capsule, or covering of the cell, the 
little granules are formed, which, I told you, float about in the 
fluid contents of the cell. These increase in number, and the 
external gelatinous case becomes distended, and adapts itself 
to the growing substance within. The latter soon divides into 
two parts, either in a direct line across the cell (pi. vi. fig. 3), or 
oblicpiely; and these two parts, which are in reality two new 
cells, burst the outer coat, and swim away (furnished with two 
cilia for the purpose) to be nourished, subdivided, and repro- 
duced in the same manner as the parent cell. There are other 
stages into which they pass ; but this is the first and essential 
process by which they are multiplied with incredible rapidity. 
The chief difference between the simple little cell, that I have 
been describing to you, and Volvox globator (pi. v. large globe), 
the *’ rolling globe/ is that the latter is an aggregation or assem- 
blage of the former, which, instead of escaping after they have 
subdivided, remain permanently attached to one another , and 
form that beautiful little globe which has so greatly excited your 
admiration this evening. You will recollect that it presented 
the appearance of a crystal ball studded all over with objects 
resembling emeralds, connected together by delicate lines, and 
within it there were eight smaller globes, of a deep green 
colour. A smaller globe also, similar to those within the larger 
one, you will remember, was revolving a little to the right of 
the latter,* and I will now endeavour to explain to you the 
relationship existing between the globes. 
First of all, a simple vegetable cell filled with green granules 
(pi. vi. fig. 2, 3) undergoes the process of subdivision into two 
parts, as already described. Then, instead of these two parts 
becoming detached from one another, each again subdivides, and 
so the process of ‘ segmentation/ as it is called, goes on (pi. vi. 
figs. 4, 5, 6, 7) until the whole mass of cells assumes the appear- 
ance of a mulberry. Unlike the mulberry, however, it is hollow, 
and is surrounded by a transparent gelatinous capsule (pi. vi. 
* The reader should refer to the plate when necessary. 
