356 STUDIES IN ADVANCED PHYSIOLOGY. 



asked than answered. The physiological significance of 

 this change from peptones into the albumens of the blood 

 is apparent. In the first place the peptones act as poisons 

 in the blood. In the second place, being changed back into 

 albumens they are robbed of their dialyzing power, and so 

 there is prevented, possibly, the loss of the albumens in 

 kidneys or glands, or even back again into the intestine, for 

 peptones would dialyze into the intestine as easily as out 

 of it. 



THE ABSORPTION OF THE SUGARS. 



No serious difficulty presents itself in understanding the 

 absorption of the sugars. By the digestive actions of the 

 ptyalin and the amylopsin, all the starches are changed 

 to maltose, and finally by the action of the ferment in the 

 intestinal juice all the various sugars taken in our diet, and 

 the maltose derived from the starch are changed into dex- 

 trose or grape sugar in their passage through the abdominal 

 wall. In the form of dextrose it reaches the blood, and by 

 the portal circulation is carried to the liver, where it is 

 affected in a manner soon to be described. 



THE ABSORPTION OF THE FATS. 



A greater difficulty presents itself in understanding the 

 absorption of fats. That portion of the fats which is 

 saponified and so rendered soluble (for soaps are soluble), 

 will readily dialyze into the blood, but most of the fat is ab- 

 sorbed in its solid form; that is, in the form of finely 

 emulsified droplets. A histological examination of the 

 small intestine during fat-absorption shows droplets of fat 

 in the epithelium cells, between them, and even under them, 

 reaching into the lacteals. It is, of course, out of the ques- 

 tion here to speak of physical osmosis. Droplets cannot 

 filtrate. We are driven to the conclusion that it is the 

 epithelium cells that line the intestine which actively pick 

 them up; that is, ingest these droplets of fat into their 

 bodies, pass them along through their protoplasm, and 

 finally eject them again from the under side into the spaces 



