76 Miss M. P. FitzGerald. The Origin of the [June 4, 
instead of the potassium salt, the reaction was produced in the filtrate of the 
contents of this region to a marked degree. A similar result was obtained 
in Rabbit 5. On the other hand, the reaction was usually obtained in the 
filtrate of the contents removed from the intermediate region; or, in other 
_ words, in the filtrate of the contents contiguous or adjacent to that part 
of the mucosa to which the Prussian blue deposit generally adhered. 
Occasionally, a very faint reaction was obtained in the filtrate of the 
contents of the pyloric region. In Rabbit 6, the hematoxylin reaction was 
obtained in the filtrate pertaining to the intermediate region, and in that 
of the upper part of the pyloric region; but not in the filtrate of the 
contents removed from the superior half of the organ in this region. It 
is of interest to note that in the control (uninjected) rabbit, the Prussian 
blue reaction was also obtained in the filtrate of the contents of both the 
intermediate and pyloric regions, on the addition of hydrochloric acid and 
potassium ferrocyanide; but the reaction was slight in comparison to that 
obtained in the injected animal. This appears to indicate an excretion of 
iron by the cells of the gastric mucosa, since only a small quantity of iron 
could have been derived from the food (carrots). In the analysis of carrots 
given by Rottger,* the ash represents 1:03 per cent. of the total material, and 
of this ash, iron (Fe,Q3) represents 1:01 per cent. In certain instances, 
notably in Rabbit 3, the Prussian blue reaction was obtained in the filtrate of 
the contents of the upper portion of the duodenum. 
As before stated, a deposit of Prussian blue was observed adhering to the 
surface of the mucosa and in the gastric contents of each species of animal 
experimented upon, being present, frequently to a marked degree, in the 
majority of the rabbits, in each of the three guinea-pigs, and, in a ininor 
degree, in one of two dogs employed. 
The earlest observed occurrence of the deposit on the surface of the 
mucosa was three hours after the first injection: but as a minimum period 
of three hours, dating from the first injection, was allowed to elapse before 
any of the animals were killed, no information can be supplied from the 
present series of experiments as to the earliest appearance of the. deposit. 
It will, however, be recalled that Claude Bernard observed a superficial 
deposit three-quarters of an hour after the injection of the lactate of iron 
and potassium ferrocyanide. 
A statement in reference to the earliest observed excretion by the kidneys 
of the two salts injected in solution will be found on p. 73. 
In the rabbit and the guinea-pig the Prussian blue thus observed on 
opening the stomach was invariably situated in a comparatively speaking 
* Rottger, ‘ Nahrungsmittel-Chemie,’ 3rd ed., p. 344. | 
