METABOLISM AND THE DISTRIBUTION OF MATERIAL 247 



pp. 283 to 286), which, in spite of their considerable diameter, change 

 their shape so that they pass through the finest vessel walls. If to the 

 leucocytes is to be attributed a share in the resorption of fat, they 

 must journey into the intestines and return laden with fat. It has 

 not been possible as yet to decide microchemically whether fat passes 

 the intestinal epithelium unchanged. [In the presence of protective 

 colloids, colloidal gold will pass through Pukall filters which other- 

 wise hold them back. ZSIGMONDY-ALEXANDER, Colloids and the 

 Ultramicroscope, p. 153, et seq. Tr.] 



One fact, at least to me, seems very much to favor the idea that 

 fat may be resorbed unchanged from the intestines, namely, linseed 

 oil, sesame oil, cottonseed oil, etc., may occur unchanged in the 

 milk, and foreign fats (rapeseed oil) may be deposited in the body. 

 Absorption occurs almost exclusively in the small intestines (NAKA- 

 SHIMA). Within the intestinal wall, neutral fat may be synthesized 

 from the absorbed fatty acid alkali and glycerin, so that neutral 

 fat is carried to the body in very fine emulsion through the chyle 

 ducts, and in fact fat may enter the blood stream directly. 



The milky turbid lymph collects in the thoracic duct and empties 

 into the subclavian vein. It is especially easy after the ingestion of 

 fat to recognize ultramicroscopically, in the blood, numerous gran- 

 ules (hemoconia), which* may be considered fat droplets (A. NEU- 

 MANN,* K. REICHER*). 



It is possible, therefore, to follow visually the path of fat by means 

 of dark field illumination. S. BONDI and A. NEUMANN* experimented 

 as follows : at times, they caused hemoconia to appear in the blood 

 by a liberal fat diet, and at others they injected a very fine emulsion 

 of fat into the veins. Large fat droplets suspended in blood are evi- 

 dently unable to change their form, and as a result cause emboli in 

 the lungs, which may prove fatal. These investigators experimented 

 thus with emulsions of lanolin, cholesterin, lecithin, butter and 

 olive oil, whose particles were only recognizable in the dark field. 

 They dissolved the fat they were using in alcohol and poured the 

 alcoholic solution slowly into water with constant stirring. The 

 alcohol was removed from the filtrate of this emulsion by gently 

 warming it on a water bath. 



S. BONDI and A. NEUMANN then established that the fat droplets 

 were not dissolved by lipolytic ferments during their sojourn in the 

 blood. 1 They are emulsified by the venous blood in the right heart, 

 and after they have passed the capillaries of the lesser circulation, 

 they enter those of the greater circulation. Their goal, like that of 



1 In my opinion such emulsions of uniform particle size could serve in measur- 

 ing the exact dimensions of the smallest capillaries under normal conditions. 



