436 MR. A. LISTER ON THE INGESTION OF FOOD-MATERIAL 
contact with ameboid swarm-cells, they coalesced ; the investing 
hyaloplasmie substance offered for a time a resistance to union, 
this at length gave way, and the contents of one gushed into the 
other. When a microcyst was met with in the line of march, it 
was taken in as foreign matter and enclosed in a vacuole ; it was 
slowly absorbed in the course of three or four hours. 
Active swarm-cells, which had probably hatched out later 
than the others, though often seen to approach the plasmodia, 
and even to lie for some minutes enfolded by their pseudopodia, 
never coalesced, and in time wandered away again. The plasinodia 
did not all unite, but continued to crawl over the glass for four 
days longer, when the conditions became unfavourable, and they 
dwindled away without developing into sporangia *. 
Referring to the process of nutrition in the Mycetozoa, 
De Bary states t “that the food is taken in during the swarm- 
cell condition only in a fluid state or state of solution, and this 
is also the case, at least in most instances, with the plasmo- 
dium." 
This is a point on which there has been some controversy. 
Mr. Saville Kent, in the appendix to his * Manual of the Infu- 
soria, described in 1881 the appearance of swarm-cells of Phy- 
sarum tussilaginis, which contained vacuoles filled with bacteria 
of the same kind as abounded in the surrounding medium. He 
also relates how, on adding pulverized carmine to the water, the 
granules were freely ingested, and, as in the case of the bacteria, 
were collected within ‘ spheroidal vacuoles.” 
Although this experiment clearly shows that the swarm- cells 
of Physarum tussilaginis take in food-material in other than in 
the fluid state, yet as De Bary’s high authority, published so 
* In sowings of Chondrioderma difforme spores on blotting-paper with cress 
seeds, I have always found the sporangia begin to form in eleven to fourteen 
days from the date of sowing, and may continue to make their appearance for 
four months. 
I have had the plasmodium of Badhamia utricularis in constant streaming 
movement for more than a year, though many cultivations from the original 
stock of plasmodium have changed to sporangia at different intervals during 
that time.  Sclerotium of the last named species, after two years' preservation, 
has changed to sporangia within a fortnight of being revived; while other 
plasmodium, revived from the same sclerotium, has continued to stream with- 
out change for five months, although both were fed with Stereum hirsutum, and 
were apparently under precisely the same conditions. 
t De Bary, Mycetozoa, Oxford edition, p. 452. 
