“gs 
Cuap. HI.) THE PROCESS OF AGGREGATION. 49 
the proper rate. Some tentacles in a drop of water were 
strongly pressed beneath a slip of glass; many of the cells 
were ruptured, and pulpy matter of a purple colour, 
with granules of all sizes and shapes, exuded, but hardly 
any of the cells were completely emptied. I then added 
a minute drop of a solution of one part of carbonate of 
ammonia to 109 of water, and after 1 hr. examined the 
specimens. Here and there a few cells, both in the glands 
and in the pedicels, had escaped being ruptured, and their 
contents were well aggregated into spheres which were 
constantly changing their forms and positions, and a current 
could still be seen flowing along the walls; so that the 
protoplasm was alive. On the other hand, the exuded 
matter, which was now almost colourless instead of being 
purple, did not exhibit a trace of aggregation. Nor was 
there a trace in the many cells which were ruptured, but 
which had not been completely emptied of their contents. 
Though I looked carefully, no signs of a current could be 
seen within these ruptured cells. They had evidently been 
killed by the pressure; and the matter which they still 
contained did not undergo aggregation any more than that 
which had exuded. In these specimens, as I may add, the 
individuality of the life of each cell was well illustrated. 
A full account will be given in the next chapter of the 
effects of heat on the leaves, and I need here only state that 
leaves immersed for a short time in water at a temperature 
of 120° Fahr. (48°°8 Cent.), which, as we have seen, does not 
immediately induce aggregation, were then placed in a few 
drops of a strong solution of one part of carbonate of 
ammonia to 109 of water, and became finely aggregated. 
On the other hand, leaves, after an immersion in water at 
150° (€5°°5 Cent.), on being placed in the same strong 
solution, did not undergo aggregation, the cells becoming 
filled with brownish, pulpy, or muddy matter. With leaves 
subjected to temperatures between these two extremes of 
120° and 150° Fahr. (48°°8 and 65°°5 Cent.), there were 
gradations in the completeness of the process; the former 
temperature not preventing aggregation from the subsequent 
action of carbonate of ammonia, the latter quite stopping it. 
Thus, leaves immersed in water, heated to 130° (547-4 Cent.), 
and then in the solution,formed perfectly defined spheres, but 
these were decidedly smaller than in ordinary cases. With 
other leaves heated to 140° (60° Cent.), the spheres were 
E 
Mo. Bot. Garden, 
1202 
