1910. | Hydrochloric Acid wn the Gastric Tubules. pak 
It is likewise not known that either salt diffuses through all the tissues of 
the body with a uniform velocity, the observations of Ranvier previously 
mentioned, p. 61, point to the contrary in the case of potassium ferrocyanide, 
so that a solution which in a test-tube is “balanced” may not be so in the 
gastric mucosa. Therefore it is better for the object in view to have an 
excess of the double citrate, so that in the gastric tubules a complete disposal of 
all the ferrocyanide can be effected, and thus enable the gland-cells engaged 
in the formation of hydrochloric acid to demonstrate the presence of the acid 
in such structures. 
The animals selected for the investigation were the dog, the rabbit, and 
the guinea-pig. Their physiological condition as regards digestive activity 
varied from one of semi-starvation to one of full digestion. 
The injection fluid was freshly prepared at the time of injection by taking 
equal parts of a 1:5-per-cent. aqueous solution of potassium ferrocyanide and of 
a 2°25-per-cent. aqueous solution of ammonium ferric citrate. 
In one instance sodium ferrocyanide was substituted for the potassium 
salt, but no appreciable difference in results was observed. 
The total amount of fluid injected, by two or more injections given at 
varying intervals, varied from 10-11 to 45 ec. cms. in rabbits; from 16 
to 22 c.cms. in guinea-pigs; and from 42 to 55 c. ems. in dogs. 
The subcutaneous method was employed as a rule, and was found to give 
the best results. The flank was the region selected for injection in the dog 
and the rabbit, and the abdominal region in the guinea-pig. In one case 
(rabbit) the injections were given intravenously (lateral branch of the 
posterior auricular vein), and in another (rabbit) an intravenous injection 
was supplemented by two given by the subcutaneous method. 
In many instances, but not in all, toxic effects were produced during life 
by the solution injected, and these varied somewhat in the different animals. 
By a process of exclusion, the toxic effect could be attributed to the 
potassium ferrocyanide, as experiments made by Prof. A. B. Macallum 
showed that large doses of the double citrate could be injected into rabbits 
without causing any physiological disturbance. 
The toxic effects were manifested by refusal of food, by discomfort, 
restlessness and agitation, or by lethargy. Inflammatory conditions super- 
vened at the site of inoculation in the guinea-pig, and much gas was found 
in the stomach and intestines. Diuresis was observed in the guinea-pig, 
and there were indications of this also in the rabbit, but in the dog, 
diminution in quantity, or suppression, of urine ensued. In the first 
dog experimented upon vomiting occurred once, but apart from this 
no marked disturbance was observed. In the second dog lethargy was a 
