1902.] NATURAL SCIENCES OF PHILADELPHIA. 338 



the intestine was fixed after fifty houi-s, when many globules are 

 still to be seen in other slides of the series. 



The first experiment mentioned above furnishes additional proof 

 that the globules found in the cells are fat. Since there can be no 

 question about the identity of the globules in the second experiment, 

 it shows that osmium-fixed fat globules are practically insoluble in 

 ordiuary fat solvents. This is not true of fat outside the cells — 

 that is, while still in the lumen. 



Sections of intestine of an animal fed for twenty minutes on 

 butter and fixed after seventy-five hours in Flemming's fluid with- 

 out acetic acid, were mounted and stained in acid-fuchsine in the 

 usual way. Instead of mounting in thick balsam, a large amount 

 of oil and a little balsam wei'e placed on the section. The next 

 day the fat, densely blackened and enclosed by the epithelial wall, 

 was seen to be diffusing out, and in a week it was entirely dis- 

 solved by the excess of cedar oil. The cells of the epithelium, 

 however, still contained abundant globules blackened by the osmic 

 acid. 



That the globules last mentioned did not dissolve may be ex- 

 plained by supposing the fat inside the cell to be mixed with some 

 coagulable substance. 



Butter spread on a cover-glass and treated with Herman u's fluid 

 for fifteen hours, then with ether (after dehydration), leaves a 

 coagulated residue which retains its black color for more than two 

 days in the solvent. Again, in teasing out in Hermann's fluid an 

 intestine whicli had been filled with olive oil, it was observed tliat 

 the oil, mixed with the secretion of the hepatopancreas, on escaping 

 in the form of globules, took a brownish color at the jieriphery and 

 the densely black color within. The brown color may have been 

 due to fatty acid or to a film of the coagulated secretion. 



Finally, as Altmann has observed, decomposition products or 

 other diluting substances are probably responsible for the different 

 degrees of intensity with which the osmium-blackening occurs or 

 remains after treatment with solution agents (loc. dt, p. 98). It 

 is scarcely possible to suppo.se that the globules of fat inside the cell 

 are wholly unmixed with the albuminous fluid contents of the cell, 

 or with the immediate products of digestion. 



The whole evidence for fat in the cells may be summarized as 

 follows: (a) Oily globules are seen in the cells of fresh intestines 

 from animals fed with fat; (6) these globules are dissolved by 

 xvlol after fixation in PtCl^ (and certain other reagents — HgClj, 



