Cuar. III, THE PROCESS OF AGGREGATION. 47 
stream of protoplasm on the walls of the cells ceases to be 
visible; I observed this fact repeatedly, but will give only one 
instance. A pale purple leaf was placed in a few drops of a 
solution of one part to 292 of water, and in 2 hrs. some fine 
purple spheres were formed in the upper cells of the pedicels, 
the stream of protoplasm round their walls being still quite 
distinct; but after an additional 4 hrs., during which time 
many more spheres were formed, the stream was no longer 
distinguishable on the most careful examination; and this no 
doubt was due to the contained granules having become united 
with the spheres, so that nothing was left by which the move- 
ment of the limpid protoplasm could be perceived. But minute 
free spheres still travelled up and down the cells, showing that 
there was still a current. So it was next morning, after 22 hrs., 
by which time some new minute spheres had been formed; 
these oscillated from side to side and changed their positions, 
proving that the current had not ceased, though no stream of 
protoplasm was visible. On another occasion, however, a 
stream was seen flowing round the cell-walls of a vigorous, 
dark-coloured leaf, after it had been left for 24 hrs. in a rather 
stronger solution, namely, of one part of the carbonate to 218 of 
water. This leaf, therefore, was not much or at all injured by 
an immersion for this length of time in the above solution of 
two grains to the ounce; and on being afterwards left for 24 hrs, 
in water, the aggregated masses in many of the cells were re- 
dissolved, in the same manner as occurs with leaves in a state of 
nature when they re-expand after having caught insects. 
In a leaf which had been left for 22 hrs. in a solution of one 
part of the carbonate to 292 of water, some spheres of proto- 
plasm (formed by the self-division of a bag-like mass) were 
gently pressed beneath a covering glass, and then examined 
under a high power. They were now distinctly divided by 
well-defined radiating fissures, or were broken up into separate 
fragments with sharp edges; and they were solid to the centre. 
In the larger broken spheres the central part was more opaque, 
darker-coloured, and less brittle than the exterior; the latter 
alone being in some cases penetrated by the fissures. In many 
of the spheres the line of separation between the outer and 
inner parts was tolerably well defined. The outer parts were of 
exactly the same very pale purple tint, as that of the last 
formed smaller spheres; and these latter did not include any 
darker central core. 
From these several facts we may conclude that when vigorous 
dark-coloured leaves are subjected to the action of carbonate of 
