seen, under a Beck’s Juth immersion lens, to be drawn in and
conveyed into freshly formed vacuoles.
“ I have repeatedly seen bacteria taken by swarm-cells of
Chondrioderma diffonne in the manner above described, and it
would appear that bacteria form their principal food. On one
occasion I had a favourable opportunity for observing the
digestion of bacilli on account of the quiescent state assumed
by a swarm-cell, which remained with little active movement
for an hour and a half. On the previous evening I had placed
some spores of Ghondrioderma difforme in water under a thin
cover-slip; on the following morning swarm-cells were in great
abundance in the pure water. I introduced a drop containing
multitudes of bacilli from a glass in which a piece of Stereum
h,irs%itum had been soaking for several days. In a short time
a number of the swarm-cells were seen, attended by bacilli,
some of which were attached to their pseudopodia, and some
were already enclosed in vacuoles. The swarm-cell in question
had taken an amoeboid form, occasionally producing and again
withdrawing the cilium, while from time to time thin pseudopodia
were extended from the opposite end, but more frequently
the posterior region expanded into a somewhat funnel-shaped
mouth. Into such an expansion a stout bacillus, about 2 p long,
w’as seen to enter; in the course of a few seconds it was
enclosed with a noticeable amount of water, by the folding over
of the lips of the funnel, and conveyed into the body-substance;
a few minutes after, another bacillus was taken in, much in
the same manner, but no globule of water was introduced. Ten
minutes later a large bacillus, 4i p xO'75 p, was caught by a
prolongation of one side of the funnel, and in the course of
half a minute a tube-like extension of protoplasmic substance
invested the bacillus, and it was drawn in. I t remained for
a short time in direct contact with the granular matter of the
body, but was soon surrounded by an oval vacuole. The
swarm-cell continued inactive for nearly an hour, when it
assumed au extended form, and shortly after swam away with
rapid jogging movement. Constant observation was maintained
during this hour, and the bacilli were seen gradually to dissolve
in the vacuoles in which they lay, until at length all trace of
them had disappeared together with their containing vacuoles,
and only the contracting vacuole remained in the homogeneous
granular substance of the swarm-cell.
“At the commencement of the observation this granular
protoplasm was much more turbid than at the close, when it
was remarkably hyaline ; the swarm-cell appeared also to have
increased in size, though it was difficult to determine by
measurement in consequence of its changing form. No rejection
of refuse matter took place while the observation lasted.
“ In the same preparation I watched a swarm-oell creeping in
a straight line with the strange snail-like movement, so difficult
to understand. In its course it came to a small group of motionless
bacilli lying against the glass; immediately it changed
its linear form and spread itself out, covering four of the bacilli.
In about two minutes it resumed its former shape and movement
and crept away, carrying off two of the bacilli in vacuoles.
“ These observations seem to confirm the opinion of De Bary,
that the organisms under consideration should be classed among
the animal rather than the vegetable kingdom, which led him
in 1858 to adopt the term Mycetozoa in place of that of
Myxomycètes for the group. When a creeping swarm-cell is
watched, with the projecting cilium placed immediately in
advance of the nucleus, which never shifts its position, and
when, as in the last-mentioned case, we note the manner in
which the vibrating extremity of the cilium appeared to detect
the presence of the bacilli before the swarm-cell spread itself
over them ; again, when we observe the creeping action suddenly
change, and raising itself from the decumbent attitude, with a
few lashing strokes of the cilium the swarm-cell releases its
foot-hold and swims away ; and when to these remarkable
movements is added the process of ingestion which has been
described ; we cannot but feel the force of the conclusion at
which De Bary arrived, if indeed a distinct line of demarcation
between the two kingdoms can he said to exist.” ’
The brilliant and pure colours presented by the plasmodia of
’ Notes on OJwndrioderma difforme and other Mycetozoa; Ann. Dot.,
Vol. IV. No. xiv. (May 1890), pp. 281—298, 1 pi.