ANATOMY OF THE ALIMENTARY CANAL. 
467 
as I have shown that the reticulum is attached in preparations hardened in chromic 
acid, I conceive them to be sufficiently convincing. 
Fat-absorption by the Beticulum among the Epithelial Cells. 
To obtain preparations showing the fat between the epithelial cells, an animal was 
killed during the absorption of fat, and the intestine hardened in osmic acid, according 
to the methods given above; small portions of the mucous membrane were teased. 
The teased preparations were then treated with a dilute solution of caustic potash, until 
the tissue became much more transparent ; they were then placed in glycerine. If, in 
such a preparation, a horizontal view of separated epithelial cells be examined, it is seen 
that fat-granules are arranged in lines between the cells, the epithelium being free 
from fat-particles (see Plate 41. fig. 23). 
In examining sections of an intestine hardened as above, if we view the epithelium 
where it has been cut transversely, we have appearances very similar to those we have 
just described, i. e. the fat-granules are arranged in lines between the epithelial cells. 
If in the section the epithelium be cut vertically, although there are distinct lines of fat- 
granules between the cells, yet, as a rule, the appearances are not so satisfactory, as 
the cells appear to contain particles of fat. 
Examination of teased preparations will show isolated epithelial cells apparently 
filled with fat, as has been figured and described by so many observers. It must, how- 
ever, he remembered that the reticulum always breaks off with the epithelium, and that 
it is difficult to decide whether the fat which we see apparently in the epithelial cells 
is lying in them or in the shreds of reticulum attached to them ; by pressing on the 
cover-glass and rolling over these isolated epithelial cells, the fat is generally seen to 
be arranged in lines along their borders. 
From the foregoing observations I have concluded that there is proof that the fat 
travels by the reticulum between the epithelial cells , but that there is no decisive evidence 
that fat-granules are absorbed by the epithelial cells. 
This reticulum has been seen and described by a great number of observers under 
various names. It has been seen in the most different epithelia ; it has been shown to 
be capable of absorbing various substances ; and there are some observations which 
prove that injections have penetrated into it. 
Thus, Reich (109), Pfluger (62), Heidenhain (110), Langerhans (63), Gianuzzi (64), 
Boll (65), Saviotti (66), Ewald (67), Ebner (68), Leydig (69), and Latschenberger 
(70), have seen it in the salivary glands or pancreas ; while it was described as nervous 
tissue by Reich (109) and Pfluger (62), or as connective-tissue by Boll (65), it was 
injected and considered to be intercellular salivary capillaries by Gianuzzi (64), Langer- 
hans (63), Saviotti (66), Boll (71), and Ewald (67) ; Leydig (69) and Latschenberger 
(7 0) thought that there were only intercellular spaces between the cells ; Heidenhain 
(110) concluded that this tissue was a continuation of the cell-membrane; Ebner (68) 
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