392 LECTURE XVII. 



the question for us to attempt to picture the course of the iron through 

 the organism, and to decide how much inorganic iron is absorbed, and 

 for how long. 



The conditions which we meet with in the case of iron as regards its 

 absorption and elimination are similar with other elements. Apparently 

 other inorganic elements are taken up in about the same way and are 

 similarly eliminated. Thus we know that if we add lime l to the food, a 

 part of it is eliminated in the urine, whereas a considerable portion is 

 deposited in the large intestine. Inorganic elements which are not usually 

 found in the organism follow the same course. Thus, Steinfeld 2 found 

 that subcutaneous injection of bismuth into birds caused the vermiform 

 process and large intestine to be colored black. The relations of elimi- 

 nation are similar with mammals. Thus Steinfeld found on repeating 

 this experiment with dogs and cats that the lymph vessels of the intestines 

 were filled with a black substance. 



The fact that when iron was administered, a part of the dose was 

 absorbed in the duodenum, and then again eliminated at the end of the 

 intestine, does not tell us what happens to the iron that is contained in 

 our ordinary food. This had to be determined by a direct experiment. 

 It was found 3 that animals fed exclusively upon meat or exclusively upon 

 vegetables gave exactly the same reactions for iron in the intestines and 

 in the tissues as those which were dosed with iron salts. The behavior of 

 the hemoglobin and hematin was particularly interesting. Both of these 

 compounds contain iron in a form which renders it impossible to detect 

 it by the ordinary chemical reactions. If now a rat was fed with milk 

 containing either hematin or hemoglobin, while another rat was fed with 

 milk alone, then the alimentary canal of the latter would not give any 

 iron reaction, whereas if the intestinal tract of the first rat was placed 

 in a solution of ammonia and ammonium sulphide, an intense green color- 

 ation appeared at once. Thus the iron has been loosened from its state 

 of combination in hematin; it has evidently become ionized. This shows 

 it is extremely probable that unchanged hematin is not absorbed as such. 

 The formation of hemoglobin in the animal organism is in all cases the 

 result of a synthesis or a change in the way in which the iron is combined. 

 This assumption cannot at present be verified definitely, because, as we 

 have mentioned, it is possible that besides the compounds in which we are 

 able to detect iron by the ordinary reagents, there may be others present 



1 R. W. Raudnitz: Arch, exper. Path. Pharm. 31, 343 (1893) ; J. G. Rey: Deut. med. 

 Wochschr. No. 35, 569 (1895). G. Riidel: Arch, exper. Path. Pharm. 33, 79 (1894). 

 J. G. Rey: ibid. 36, 295 (1895). 



3 Dissertation, Dorpat, 1884. Meyer and Steinfeld: Arch, exper. Path. Pharm. 20, 

 40 (1886). 



3 Emil Abderhalden: loc. cit. 



