356 DIGESTION AND KESORPTION OF FATS 



suggesting a sieve-like purpose? ... I am well aware 

 that this is all based on probabilities, and would not care to 

 bring it forward if there were clear proof evident on the 

 other side. But there, too, I recognize nothing but argu- 

 ments based upon probability. For even if anyone had 

 proved that in this or that particular instance all the fat had 

 undergone cleavage or saponification before being absorbed, 

 it would be far from proving that invariably this is the case 

 or even usually true. ' ' 



Many histological studies have been made to come nearer 

 the solution of the secrets of fat resorption. The synthetic 

 production of fat from soaps and glycerol formerly main- 

 tained by many has as a fact not been confirmed by experi- 

 ments upon excised living intestinal mucosa ; 18 studies from 

 Fano 's laboratory in Florence 19 have, on the contrary, 

 shown that the epithelial cells of the intestinal mucosa when 

 brought in contact with oleic acid or a solution of sodium 

 oleate become loaded with fatty acid which can be demon- 

 strated by staining with osmic acid ; neutral fat, however, 

 is not taken up. We are in this case undoubtedly dealing 

 with a true physical solution phenomenon, one not mani- 

 fested by the epithelium of the oesophagus and stomach, but 

 which can be demonstrated with intestinal mucosa even 

 when hardened in f ormol, and which is probably due to some 

 solvent which the cells contain for oleic acid. 



Formerly a great deal of importance was ascribed to 

 tracing the fat droplets in their passage through the epi- 

 thelial cells of the intestine. For example, observations like 

 those of Cuenot upon the intestine of Crustacea, in which the 

 fat globules are apparent only in the portion of intestinal 

 epithelium exposed to the lumen, were regarded as particu- 

 larly valuable. Since we have come to realize that fats may 

 be masked in the presence of proteins so that they are no 



"O. Frank and A. Hitter (Physiol. Instit., Munich), Zeitschr. f. Biol., 4?, 

 251, 1906; Moore, Proc. Roy. S'oc., 72, 134, 1903. 

 19 G. Rossi, Arch, di Fisiol., 5, 381, 1908. 



