Cuar. IIL] THE PROCESS OF AGGREGATION. 39 
tion was visible in 3 m.; but after 15 m, small spheres of proto- 
plasm were formed, more especially beneath the long-headed marginal 
glands; the process, however, in this case took place with unusual 
slowness. In 25 m. conspicuous spberical masses were present in the 
cells of the pedicels for a length about equal to that of the glands; 
and in 3 hrs. to that of a third or half of the whole tentacle. 
If tentacles with cells containing only very pale pink fluid, and 
apparently but little protoplasm, are placed in a few drops of a weak 
solution of one part of the carbonate to 4375 of water (1 gr. to 10 oz.), 
and the highly transparent cells beneath the glands are carefully 
observed under a high power, these may be seen first to become 
slightly cloudy from the formation of numberless, only just perceptible 
granules,* which rapidly grow larger either from coalescence or from 
attracting more protoplasm from the surrounding fluid. On one 
occasion 1 chose a singularly pale leaf, and gave it, whilst under the 
microscope, a single drop of a stronger solution of one part to 437 
of water; in this case the contents of the cells did not become 
cloudy, but after 10 m. minute irregular granules of protoplasm 
could be detected, which soon increased into irregular masses and 
globules of a greenish or very pale purple tint; but these never 
formed perfect spheres, though incessantly changing their shapes and 
positions, 
With moderately red leaves the first effect of a solution of the 
carbonate generally is the formation of two.or three, or of several, 
extremely minute purple spheres which rapidly increase in size. To 
give an idea of the rate at which such spheres increase in size, | may 
mention that a rather pale purple leaf placed under a slip of grass was 
given a drop of a solution of one part to 292 of water, and in 18 m.a 
few minute spheres of protoplasm were formed; one of these, after 
2 hrs. 30 m., was about two-thirds of the diameter of the cell. 
After 4 hrs. 25 m. it nearly equalled the cell in diameter; and a 
second sphere about half as large as the first, together with a few 
other minute ones, were formed. After 6 hrs. the fluid in which 
these spheres floated was almost colourless. After 8 hrs. 35 m. (always 
reckoning from the time when the solution was first added) four new 
minute spheres had appeared. Next morning, after 22 hrs., there 
were, besides the two large spheres, seven smaller ones, floating in 
* [De Vries (Joc. cit. p. 59) believes 
that the form of aggregation pro- 
iluced by carbonate of ammonia is 
radically different from ordinary 
aggregation, e.g. that produced by 
meat. He believes it to be due toa 
precipitation of albuminous matter ; 
the granules thus -formed tend to 
become packed into balls, and thus 
dense masses are produced which it 
is not always easy to distinguish 
from the aggregated masses which 
De Vries believed to be formed from 
the vacuole. Glauer, in the ‘ Jahres- 
Bericht der Schl. Gesell. fiir vater 
lind. Cultur,’ 1887, p. 167, also distin- 
guishes ammonia—aggregation from 
the ordinary form of the pheno- 
menon.—F, D.] 
