1904-5.] ON THE ABSORPTION OF FAT IN THE INTESTINE. ‘257 
possible to differentiate a neutral fat from one of the fatty acids since it 
gives just as distinct a reaction with oleic and stearic acids as with neutral 
fats. Consequently one cannot say positively whether the droplets are 
fatty acids or neutral fat, although in all probability the latter. If, how- 
ever, they are fatty acids, these are absorbed in particulate form and not 
in solution. The conclusion arrived at, therefore, from the study of the 
above results is that fat is taken up in particulate form by the striated 
border, either as neutral fat, or fatty acid,—in short as an emulsion. 
Both J. Munk* and Will} have shown that the organism, probably 
the epithelial cells, can furnish the glycerine radicle necessary for the 
synthesis of neutral fat from fatty acids so that it is immaterial as to the 
ultimate result whether the fat is taken up in a neutral form or as a fatty 
acid. 
Hofbauert performed certain experiments to show that fat was taken 
up as an emulsion. Before feeding, the fat was stained with Alkanna 
Roth or Lackroth A. These are insoluble in water, but soluble in alcohol. 
On examination he found the fat in the villi stained. Pfltiger, in criticiz- 
ing Hofbauer’s work points out that the stains used are soluble in bile, 
glycerin and soap so that the stain might readily be absorbed and colour 
the fat afterwards. Hence one cannot draw any positive conclusions 
from Hofbauer’s researches. I repeated his experiments, using scarlet 
red, which has one advantage over Hofbauer’s stains in that it is insoluble 
in glycerine. It is, however, soluble in soap solution. The fat in the 
villi was found to be coloured red. Nevertheless, when taken in conjunc- 
tion with the demonstration of fat inthe border it is a fact in support of 
the emulsion theory of fat absorption. 
Henriques and Hansen§ conclude from their experiments that all fat 
is absorbed as soap. They took equal parts paraffin and fat with a little 
fatty acid and added an aqueous solution of sodium carbonate. There 
results an emulsion in which the droplets contain an equal quantity of 
fat and paraffin intimately mixed. On feeding this they found that most 
of the fat was absorbed while the paraffin was in the excrement. Upon 
superficial consideration this seems to be a very strong objection to the 
emulsion theory. But what reason have they for supposing that their 
made up emulsion remains intact until it reaches the duodenum? Milk 
is an emulsion, but without being acted upon by the intestinal fluids 
* Virchow’s Arch., Vol. 80, p. 20 and Vol. 95, p. 431. 
+ Pfliiger’s Arch., Vol. 20, 1879, p. 255. 
t Pfliiger’s Arch., Vol. 81, p. 263, Vol. 84, p. 619 and Zeit. f. Klin. Med., Vol. 47, p. 477. 
{ Centralbl. f. Physiol., 1900, p. 313. 
