MOVEMENTS OF PROTOPLASM. 25 
the protoplasm is granular it consists of an outer thin denser 
layer or film called the ectoplasm, which is transparent and free 
from granules ; and of an inner portion known as the endoplasm, 
in which there are numerous minute particles or granules (micro- 
somata) and fibrillee so arranged as to form a kind of network. 
According to Sachs, that matter only ought to be regarded as 
protoplasm which is perfectly transparent, and the granules where 
they occur are to be looked upon as ‘probably finely divided, 
assimilated food-material.’ 
Fic. 40. 
Fig. 40. Three cells of one of the hairs of the common Potato plant (Solanum 
tuberosum), showing the circulation of the contents of each cell in reticu- 
lated currents. Inthe central cell the direction of the currents is in part 
indicated by arrows. After Schleiden.——Fig. 41. Cells of the leaf of 
Vallisneria spiralis, showing rotation of the protoplasm. A, A. Cells in 
which some chlorophyll corpuscles are passing up one side of each cell, 
across, and down on the other side. The direction of the currents is 
indicated by the arrows. 7, 7, N,N. Nuclei. c¢, c. Chlorophyll corpuscles, 
After J. W. Groves. 
The Movements of Protoplasm.—Doubtless during the whole 
time that the cells are growing the protoplasm is in a constant 
state of motion, although in many cases too slow to be observed ; 
but in some cells, such as those forming the hairs of certain 
plants—e.g. in those of the Potato (fig. 40), and those on the 
filaments of Tradescantia; or again in the cells forming the 
leaves of many water-plants, e.g. Vallisneria (fig. 41), Nitella, 
&c,—this motion is readily observable. It would seem as though 
