

ABSORPTION OF PEPTONES AND PROTEIDS. 299 



cells of which are formed by the division of the pre-existing cells.] It is asserted 

 by Salvioli that the mucous membrane possesses the property of changing peptone 

 into albumin. 



[Injection of Peptone into Blood. When peptone is injected into the blood of an animal, 

 within twenty minutes thereafter no trace of the peptone is to be found in the blood, although 

 it has not been excreted by any of the organs. Peptones so injected prevent the blood of the 

 dog (not of the rabbit or pig) from coagulating. In large quantity they are fatal. Fano asserts 

 that the peptone is taken up by the red blood-corpuscles, which thus become of greater specific 

 gravity, and change it into globulin. After three or more hours the corpuscles return the 

 globulin to the blood, so that the corpuscles represent a reserve store of proteid. The peptones 

 used in these experiments were really a mixture of peptones and albumoses. Neumeister finds 

 that in the dog, when albumoses are injected into the blood they reappear in the urine, but 

 somewhere in the body they undergo hydration in the sense in which peptic digestion causes 

 hydration. The two primary albumoses reappear almost completely as deutero-albumose, and 

 deutero-albumose, when introduced, reappears as peptone. Peptone, however, reappears un- 

 changed. In rabbits, albumose reappears unchanged in the urine.] 



(4) Unchanged true proteids filter with great difficulty, and much albumin 

 remains upon the filter. On account of their high endosmotic equivalent they pass 

 with extreme slowness, and only in traces, through membranes. Nevertheless, it 

 has been conclusively proved that unchanged proteids can be absorbed (Briicice), 

 e.g., casein, soluble myosin, alkali-albuminate, albumin mixed with common salt, 

 gelatin ( Voit, Bauer, Eichhorst). They are absorbed even from the large intestine 

 (Czerny and Latschenberger), although the human large intestine cannot absorb 

 more than 6 grms. daily. But the amount of unchanged proteids absorbed is 

 always very much less than the amount of peptone. 



Egg-albumin without common salt, syntonin, serum -albumin, and fibrin are not absorbed 

 {Eichhorst). Landois observed, in the case of a young man who took the whites of 14 to 20 

 eggs along with NaCl, that albumin was given off by the urine for 4 to 10 hours thereafter. 

 The amount of albumin given off rose until the third day, and ceased on the fifth day. The 

 more albumin taken, the sooner the albuminuria appeared, and the longer it lasted. The 

 unchanged egg-albumin reappeared in the urine. If egg-albumin be injected into the blood, 

 part of it reappears in the urine ( 41, 2) {StoTcvis, Lehmann). 



(5) The soluble fat-soaps represent only a fraction of the fats of the food which 

 are absorbed ; the greater part of the neutral fats being absorbed in the form of 

 very fine particles as an emulsion ( 192, II.). The absorbed soaps have been found 

 in. the chyle, and as the blood of the portal vein contains more soaps during digestion 

 than during hunger, it has been assumed that the soaps pass into the intestinal 

 blood-capillaries. The investigations of Lenz, Bidder, and Schmidt, render it 

 probable that the organism can absorb only a limited amount of fat within a given 

 period ; the amount perhaps bears a relation to the amount of bile and pancreatic 

 juice. The maximum per kilo, (cat) was 0*6 grms. of fat per hour. 



Perhaps the soaps reunite with glycerine in the parenchyma of the villi, to form 

 neutral fats, as Perewoznikoff and Will found neutral fats, after injecting these two 

 ingredients into the intestinal canal, while Ewald found that fat was formed when 

 soaps and glycerine were brought into contact with the fresh intestinal mucous 

 membrane. Perhaps this is the explanation of the observation of Bruch, who 

 found fatty particles within the blood-vessels of the villi. No fatty-acids are 

 found in blood, or chyle. 



Absorption of other Substances. Of soluble substan6es which are introduced into the intes- 

 tinal canal, some are absorbed and others are not. The following are absorbed : alcohol, part 

 of which appears in the urine (not in the expired air), viz., that part which is not changed into 

 C0 2 and H 2 0, within the body; tartaric, citric, malic, and lactic acids ; glycerine, inulin ; gum 

 and vegetable mucin, which give rise to the formation of glycogen in the liver. 



Amongst colouring matters, alizarin (from madder), alkannet, indigo-sulphuric acid, and its 

 soda-salt are absorbed ; hsematin is partly absorbed, while chlorophyll is not. Metallic salts 

 seem to be kept in solution by proteids, are perhaps absorbed along with them, and are partly 

 carried by the blood of the portal vein to the liver (ferric sulphate has been found in chyle). 

 Numerous poisons are very rapidly absorbed, e.g., hydrocyanic acid after a few seconds ; potas- 



