202 W. R. BLOOR 



tlio living animal with considerable exactness. The result has been a 

 accumulation of data from which we can now begin to get an insight int 

 the history of the fats after they leave the intestine. After absorptio: 

 that part of the food fat which has passed into the lacteals finds its wa; 

 into the blood stream by way of the thoracic duct in the form* of a si 

 pension of very fine particles (generally less than 1 H in diameter), 

 which the Brownian movement is marked and which give the chyle an 

 the blood plasma their milky appearance. The milkiness persists for so: 

 time but has generally disappeared in from eight to fourteen hours aft 

 the fat is eaten. According to present observations milkiness persisti 

 fourteen hours after a meal indicates an abnormality in fat metaboli 

 Emulsified fat (particles 2 to 5 JA in diameter) injected directly into th 

 veins disappears within a few minutes, the difference from alimentar; 

 lipemia being due probably to the larger size of the fat particles, althou 

 there is a possibility that the relatively small amount injected would 

 quickly removed and stored while a larger amount would not Rabben 

 found that homogenized fat (particles up to 2 JA in size) injected 

 quantity disappeared rather slowly (7 hours). The extent and duratio: 

 of the increase of the blood fat following a meal depends on the amoun 

 of fat fed and also apparently on. the level of the blood lipoids at th 

 time of feeding. When the blood lipoid level is high the maximum i 

 the blood is reached sooner and the fall from the maximum is slower th 

 is the case when the lipoid level in the blood is low. The amount of ext 

 fat in the blood does not, however, at any time represent the amou 

 which has disappeared from the intestine so that absorption by the tissu 

 from the blood must normally be rapid. The extent of alimentary lipemi 

 varies greatly in different animals. In rabbits it is very difficult if n 

 impossible to produce. In geese stuffed with rye values as high as 6 pe: 

 cent have been recorded. This is probably a cumulative value, since und 

 these conditions fat absorption must be continuous. In dogs the bl 

 fat values rarely exceed three per cent, and in humans two per cent. I 

 human beings with diabetes, lipemia, which is probably primarily of al 

 mentary origin, with values of over 20 per cent, has been recorded, an 

 while this is an extreme instance, high values are not uncommon in un 

 treated cases. The passage of fat from the blood is probably inhibited 

 in these cases, since on a low calorie low fat diet it may take a month fo: 

 values to get down to normal. 



The mechanism of the disappearance of fat from the blood is uncertai 

 Stained or otherwise distinguishable fat injected into the circulation dis- 

 appears promptly as indicated, and is found to have accumulated in the 

 liver, bone marrow, spleen and muscles in the order named which is true 

 also of other finely suspended material of other kinds. During fat diges- 

 tion the fine fat particles are found to have accumulated in various place 

 along the endothelial lining of the blood vessels. Various theories havi 



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