INORGANIC FOODS. 397 



as the original source of all substances in the animal organism can be 

 traced back eventually to the vegetable kingdom, the thought suggests 

 itself that chlorophyll serves as the building material in the formation of 

 hemoglobin. The herbivora devour this compound in considerable 

 quantities, and, on the other hand, the carnivora receive considerable 

 amounts of hemoglobin with their nourishment. Unfortunately, we 

 know nothing definite concerning the transformations which take place 

 with these two products in the alimentary canal. Of hemoglobin we now 

 know that in its absorption it is so changed that the iron in it becomes 

 detectable with ordinary chemical reagents. According to our experi- 

 ences as regards the significance of digestion, it is perfectly possible that 

 chlorophyll and hemoglobin are broken down into similar products, and 

 thus that the organs which form the blood have practically the same 

 kind of building material presented to them in each case. The actual 

 amount of chlorophyll and hematin available does not need to be very 

 large. Unfortunately, we do not know how much hemoglobin is formed 

 daily, or how much is decomposed, so that we have no data to judge as to 

 the normal extent of hemoglobin formation. 



We arrive at this line of thought because evidently the synthesis of 

 hematin is a very complicated one, and we are aware of no material from 

 which it could be formed apparently so readily as from chlorophyll or its 

 decomposition products. 1 At all events, these views do not by any means 

 imply that inorganic iron cannot take part in the formation of hemo- 

 globin. Even if we grant that the nucleoalbumins, or nucleoproteids, 

 serve as the building material of hemoglobin, it does not seem to us that 

 this makes the direct assimilation of iron impossible, for these substances 

 contain iron in a relatively loose state of combination. The formation 

 of hematin from albumin compounds containing iron must necessitate 

 quite considerable molecular rearrangements in order to get the iron in 

 the state of union known to exist in hematin. Now the question arises 

 as to whether milk possesses the material, other than iron, in sufficient 

 quantity for the formation of hematin. We have a perfect right to doubt 

 this. It would be perfectly useless to provide the organism with a suffi- 

 cient amount of hematoporphyrin, the principal component of hematin, 

 when an adequate supply of iron, the minor constituent, is not available. 

 It is far more probable that milk contains these two constituents in about 

 the same relative amounts as in hematin. It is consequently perfectly 



1 Perhaps the cleavage products of protein come into consideration as building 

 stones. Both proline and glutamic acid could furnish material for the ^pyrrole ring. 

 Plant albumins contain large amounts of glutamic acid. The reserve albumins are rich 

 in the above-mentioned amino acids. Perhaps this has something to do with the for- 

 mation of chlorophyll, and it is perfectly possible that the animal organism chooses the 

 same way for preparing its hematin. 



