36 DROSERA ROTUNDIFOLIA. (Cuap. IIL. 
under water. As I at first thought that the movements of 
the masses might be due to the absorption of water, I placed 
a fly on a leaf, and, when after 18 hrs. all the tentacles were 
well inflected, these were examined without being immersed 
in water. The cell here represented (fig. 8) was from this 
leaf, being sketched eight times in the course of 15 m. 
These sketches exhibit some of the more remarkable changes 
which the protoplasm undergoes. At first, there was at the 
base of the cell 1 a little mass on a short footstalk, and a 
larger mass near the upper end, and these seemed quite 
separate. Nevertheless, they may have been connected by a 
fine and invisible thread of protoplasm, for on two other 
occasions, whilst one mass was rapidly increasing, and 
another in the same cell rapidly decreasing, I was able, by 
varying the light and using a high power, to detect a 
connecting thread of extreme tenuity, which evidently served 
as the channel of communication between the two. On the 
other hand, such connecting threads are sometimes seen to 
break, and their extremities then quickly become club-headed. 
The other sketches in fig. 8 show the forms successively 
assumed. 
Shortly after the purple fluid within the cells has become 
aggregated, the little masses float about in a colourless or 
almost colourless fluid; and the layer of white granular 
protoplasm which flows along the walls can now be seen much 
more distinctly. The stream flows at an irregular rate, up 
one wall and down the opposite one, generally at a slower 
rate across the narrow ends of the elongated cells, and so 
round and round. But the current sometimes ceases. The 
movement is often in waves, and their crests sometimes 
stretch almost across the whole width of the cell, and then 
sink down again. Small spheres of protoplasm, apparently 
quite free, are often driven by the current round the cells ; 
and filaments attached to the central masses are swayed to 
and fro, as if struggling to escape. Altogether, one of these 
cells with the ever-changing central masses, and with the 
layer of protoplasm flowing round the walls, presents a 
wonderful scene of vital activity. 
Many observations were made on the contents of the cells whilst 
undergoing the process of aggregation, but I shall detail only a few 
cases under different heads. A small portion of a leaf was cut off, 
placed under a high power, and the glands very gently pressed under a 
