OLEOMAEGAEINE. 143 



thickened cuticle like the palms of the hand and the soles of the feet, 

 yet the locality especially adapted to it is the upper part of the small 

 intestine. Here the lining membrane is thrown into numerous folds 

 in order to increase the amount of surface, and covered with myriads 

 of minute projections resembling the pile of velvet which are techni- 

 cally called villi. Each little villus constitutes an absorbent gland. 

 Its surface is covered with columnar epithelial cells containing pro- 

 toplasm, and also little rod-like projections extending from their free 

 extremities. 



' 4 These cells rest upon a basement membrane which contains mus- 

 cular tissue so arranged as to aid in carrying along the solid particles 

 of food on their passage to the lacteals and blood vessels. 



"This membrane incloses a framework of connective tissue, in which 

 are contained the blood vessels and lacteals. The blood vessels are 

 arranged in the form of latticework around the lacteals, which latter 

 contain no perceptible openings. Now, fat is the only element of food 

 that is absorbed in the form of solid particles, at least to any extent, 

 and therefore would seem to be the most difficult of absorption. This 

 absorption of solid particles of fat has indeed always been a puzzle to 

 physiologists. The peptones and sugar are almost wholly liquefied 

 and can not be recognized by the microscope after entering the lacteals, 

 but fat is seen after reaching the lacteals in a very minute state of 

 division. On the principle of osmosis, it is easy to understand how 

 liquid foods are absorbed. Some physiologists believe that the epithe- 

 lium covering the villus is prolongated, so to speak, into the central 

 lacteal vesicle and that the fat granules pass not through but between 

 the epithelial cells along this prolongation of protoplasm, and so reach 

 the lacteal. Others believe that they pass through the cell by being 

 taken up by the protoplasm in the manner in which an amoeba takes 

 its food, and passed on to the lacteals by this protoplasmic agent, being 

 aided by contraction of the muscular element in the villus. The lat- 

 ter theory is the most satisfactory, and probably the most modern. It 

 is also believed that the layer of rods or pores projecting from the free 

 surface of the epithelium has to do with the absorption of fats. 

 Whichever theory is correct, it seems plain to us that the finer the par- 

 ticles of fat the more readily will they be absorbed. Moreover, it is 

 well known that an animal membrane moistened with water will not 

 allow the passage of emulsionized fat, but when moistened with bile 

 fat passes through it. From this fact it is quite probable that the 

 soaps formed, as previously described, perform important work in con- 

 nection with the absorption of fat. 



"Yeo says in reference to this : 'It has therefore been suggested 

 that the epithelial cells of the mucous membrane are more or less 

 moistened with bile, and the particles of fat in the emulsion are also 

 coated with a film of bile or soap. Thus they are enabled to pass into 

 the epithelial cells, in which they can be detected during digestion. 

 The bile or soapy coating of the fat particles may no doubt aid in their 

 transit through the various obstacles on their way to the lacteal radicles. ' 



u I know of but few actual experiments upon human beings as to 

 the comparative absorptivity of butter and other fats, but it is fair to 

 assume from the foregoing circumstances that butter is much more 

 readily absorbed than its sham congeners. Rubner ascertained that 

 butter was much more readily absorbed than ham fat. Randolph says 

 that cod-liver oil is absorbed with the greatest ease and to a greater 



