388 LECTURE XVII. 



the following values: 43.5 per cent C; 6.9 per cent H; 12.6 per cent N; 

 8.7 per cent P; traces of S; 0.455 per cent Fe; 0.352 per cent Ca; and 0.126 

 per cent Mg. 



It appears that we have here a compound representing a preliminary 

 stage in the formation of hemoglobin. The method of proving this, how- 

 ever, is not entirely satisfactory. The conclusion rests largely upon an 

 .elementary analysis. It need hardly be mentioned that this does not 

 mean much in the investigation of such a highly complicated organic 

 substance. A quite similar compound has been prepared by G. Walter, 1 

 from the eggs of the carp. Walter found in his preparation 48 . per cent C, 

 7.2 per cent H, 14.7 per cent N, 0.30 per cent S, and 2.4 per cent P; in 

 a second product he obtained the values 47 . 8 per cent C, 7 . 2 per cent H, 

 12.7 per cent N, 2.9 per cent P, and 0.25 per cent Fe. 



There is no doubt that the plants also, to some extent at least, con- 

 tain iron in the form of complicated organic compounds; and, in fact, it 

 seems evident that nuclein substances containing iron are present. Plants 

 rich in iron, especially spinach, are well suited for the preparation of such 

 products. By a similar treatment to that described for the preparation 

 of hematogen from egg-yolk, a product relatively rich in iron is obtained, 

 which, like hematin, is not acted upon by the juices of the stomach, 

 gives a similar elementary analysis, and shows corresponding chemical 

 reactions. These compounds are always obtained in an amorphous state, 

 so that it is difficult to judge of their purity. To attempt to draw any 

 conclusions as to their identity, or as to the relation of these compounds 

 to one another, would be extremely hazardous. 



We do not know the form in which the iron is contained in milk. The 

 amount present is so small that up to the present time it has not been 

 possible to isolate any compound containing iron. 



Starting with the hypothesis that the iron in our food is present, at 

 least to some extent, in a state of firm combination with organic material, 

 Bunge next raised the question as to whether the animal organism is so 

 constituted that it is able to absorb inorganic iron salts. It was not an 

 easy question to answer. It was customary to recognize the absorption 

 of a substance only when it, or one of its related compounds, was found 

 in the urine. This is not the case when inorganic iron salts are taken 

 into the system. 2 Only after subcutaneous introduction is there any 

 considerable amount of iron to be found in the urine. The fact that when 

 iron is incorporated into the system in this way it has a poisonous effect 

 upon the organism, gives further support to the assumption that inorganic 

 iron salts cannot pass through the intact intestine, 3 for there has never 



1 Z. physiol. Chem. 15, 477, 489 (1891). 



2 R. Robert: Arch, exper. Path. Pharm. 16, 361 (1883). 



3 H. Mayer u. Francis Williams: Arch, exper. Path. Pharm. 13, 70 (1881). 



