390 LECTURE XVII. 



liver and spleen. 1 The facts are quite different in the case of animals 

 which have been given iron with the milk. In the stomach there is ob- 

 tained but little, if any, reaction for iron, while in the duodenum there is 

 a marked green coloration. Often the reaction is localized to definite 

 zones. It is frequently found, for example, that merely the top of the 

 intestinal villi are colored green. If the tissue of the intestine is 

 examined under the microscope, numerous little kernels containing iron 

 are to be found embedded in the protoplasm of the intestinal epithelium, 

 and for the most part these are directly beneath the cuticular borders of 

 the cells. Now and then tiny leucocytes may be seen laden with innumer- 

 able little particles of iron. These are noticed in the stroma of the villi. 

 In the submucosa also, cells containing iron may be noticed once in a 

 while. In the jejunum, however, it is quite different. Here, as a rule, 

 the iron reaction is shown only in the solitary follicles and in the Peyer's 

 patches. In the ileum, the iron reaction is not, as a rule, very pronounced, 

 while the caecum and large intestine again give a strong test. Coming 

 from the intestinal canal, especially the duodenum, lymphatics filled 

 with cells containing iron may often be seen leading to the mesenteric 

 glands, which likewise show a pronounced iron reaction. The liver and 

 spleen now give a very strong test, and evidently these organs serve as 

 storage places for iron salts. The muscles and bone-marrow, etc., like- 

 wise show a green coloration when tested with ammonium sulphide. 



Before going farther, we wish to emphasize the fact that the observed 

 conditions which were obtained with mice, rats, rabbits, guinea pigs, dogs, 

 and cats, are not to be attributed to an irritating effect of the iron. It is 

 perfectly clear that if the epithelium of the intestines is injured in any 

 way, the absorption relations which normally take place in the intestines 

 will be considerably affected. Such irritation has indeed often been 

 observed in experiments where large doses of iron salts were fed to animals, 

 but in the experiments now in question the amounts of iron were very 

 small. Thus, rats were given but 0.4 to 0.5 milligram iron in the course 

 of a day, rabbits 4 milligrams, guinea pigs 2 to 3 milligrams, dogs 3 . 5 to 

 4 milligrams, and cats 4 milligrams per day in the form of ferric chloride 

 added to the milk. This small amount of iron was taken up gradually 

 in the course of the day. 



Now what is the significance of the above discoveries? The simplest 

 assumption is that iron begins to be absorbed in the duodenum, and is then, 

 to some extent at least, carried first of all to the lymphatic ducts. Obser- 

 vations made by Gaule 2 make it seem probable that part of the iron is 

 carried away to the thoracic duct, and thus reaches the circulation. It is 



1 Abderhalden: loc. cit. 



3 Deut. med. Wochschr. 1896, Nos. 19 and 24. 



