SYNTHESIS OF FATS ACCOMPANYING INTESTINAL ABSORPTION 23 
In the first place, however, such histological preparations do not con- 
clusively prove that neutral fat is synthesized in the epithelial cell, since the appearances 
might be reproduced by insoluble fatty acids deposited in the cells. In the second place, 
even assuming the appearances to be due to neutral fat, they give no quantitative 
information as to whether any fraction of the fatty constituents, absorbed in soluble 
form from the intestine, passes through the columnar cell unmodified into the lacteals 
to be changed in the abdominal lymphatic glands or elsewhere. Thirdly, as has been 
supposed by some writers on the subject, such a deposit in the intestin il cells as has 
been observed microscopically might be only a temporary one, the fat being again 
hydrolyzed to pass out towards the lacteal, so that a constant stream of fatty acid and 
glycerine has been assumed to diffuse out from the attached border of the cell. Nor, 
assuming as proven that the fatty constituents enter the columnar cell in soluble form, 
does the presence of a white milky fluid in the lacteals, containing fatty globules 
when viewed under the microscope, demonstrate that neutral fat has been synthesized 
in the intestinal cell. In the first place, as has been remarked above, regarding the 
appearances in the columnar cell, all such effects might be reproduced by free fatty acid in 
suspension, and, in the second place, no quantitative information is given by such 
observations as to the amount of conversion from soluble into insoluble constituents. 
Turning next to the nature and place of synthesis, as shown by the action of 
cells and extracts of cells concerned in fat absorption upon the constituents of neutral 
fats, we find on reviewing the literature that a good deal of attention has been given 
to this aspect of the subject by previous workers. 
C. A. Ewald 1 was the first observer who claimed to have detected such a syn- 
thetic action in vitro, from products of the intestinal cell. In a preliminary paper, 
published in 1883, he states that he was stimulated by the account of Brown and 
Herron's work upon the inverting action of dried mucous membrane upon cane sugar, 
to test whether a similar dried preparation of the mucous membrane was capable of 
synthesizing fat from an aqueous solution of soap and glycerine at the proper tempera- 
ture. This experiment with the dried cells failed, and the reason ascribed by Ewald, 
was that one has here to do with a synthetic operation, such as is peculiar to the 
metabolism of the living cell, and not a ferment action which would remain after the 
destruction of cell activity, as in the case of inversion of cane sugar. 
Ewald accordingly turned his attention to the fresh mucosa, and in two ex- 
periments, in which he divided the intestinal mucous membrane in each case into four 
portions, one of which was treated alone as a contral, while to the other three portions 
soap and glycerine were added in appropriate quantities, he believed that he had 
observed in all but one case a considerable formation of neutral fat from fatty acid 
and glycerine. 
1. Arch. f. Physiol, u Anat., Physiol. Abth., Suppt. Bel. 18S3, S. 302 
