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(1. ARNOLD. 
others. When the intestine is empty they are large and the 
vacuoles are full (fig. 11). Very soon after food has been 
taken into tlie intestine the whole cell diminishes in size, till 
at about the twenty-seven hour stage it is shrunken to a 
fifth of its original size and quite flaccid (fig. 16). In this 
condition it lies squeezed in between the columnar cells, so 
much so that sometimes these cells appear to lie quite outside 
the intestine, between the latter and the sui-rounding 
parenchyma. 
There can be little doubt that the gland cells secrete a 
digestive ferment, which is probably used entirely for the 
digestion of fat. 
AVithin a quarter of an hour after feeding it will be seen 
that the columnar cells are full of fat-globules, stained black 
by the osmic acid of the fixative (fig. 1). Even when the 
lumen of the intestine is full of blood (red corpuscles, leuco- 
cytes, etc.) no fat-globules are to be seen lying free in the 
lumen, nor can any pseudopodial extensions of the cytoplasm 
containing fat-globules of the columnar cells be seen, suggest- 
ing that the fat has been ingested in an amoeboid fashion. 
The gland-cells do not begin to return to their normal size 
till after about the forty-eighth hour, when almost all the 
columnar cells are devoid of unaltered fat, and reach their usual 
size again at about the seventieth hour. It is very noticeable 
that no ingestion of solid particles (i.e. true intra-cellular 
digestion) takes jtlace until the absorption of fat is over, and 
the latter has undergone marked changes in the columnar 
cells. A large part of the fat absorbed by the columnar cells 
is digested in the cytoplasm of these cells, but some of it 
is again passed out at their bases unaltered lying in the 
parenchyma. The fate of these extruded globules will be 
dealt with later ou. 
The fat first appears in the cytoplasm of the columnar cells 
in very small globules, which by fusing together form much 
larger ones, so that some cells within an hour after feeding 
seem to be one mass of fat. 
The researches of Munk, Aloore and Rockwood, and others 
