72 Miss M. P. FitzGerald. The Origin of the [June 4, 
pronoun¢ged symptom, and within three hours from the beginning of the 
experiment this had approached the comatose condition. The amount of the 
solution (ammonium ferric citrate and potassium ferrocyanide) injected in 
this case was 42 c.cms., two injections being given, with an interval of 
two hours between the first and the second. The weight of the dog was 
12 lbs. 
A general toxic effect was usually observed in rabbits which had received 
a large amount of the injection fluid during a short space of time, 7.e. 40 
to 50 e.cms. within the space of seven hours. Large amounts given over 
a long period were less likely to produce disturbance, and toxic effects were — 
absent when small doses were given in a short space of time, 7.e. 10 to 
17 c. cms. in five hours. 
These observations are in close agreement with some of those of 
Combemale and Dubiquet.* These investigators administered by the 
stomach an aqueous solution of potassium ferrocyanide to dogs and guinea- 
pigs, the doses varying from 0°08 gramme to 2 grammes per kilo. of body 
weight. They found that in the dog the repeated use of the salt caused an 
irritation of the alimentary canal, manifested by diarrhea and vomiting, 
the latter symptom being invariably present when the dose attained or 
exceeded 80 centigrammes per kilo. of body weight, whatever the con- 
centration of the fluid, and that suppression or diminution in quantity of 
urine sometimes ensued, but diuresis never, while in the guinea-pig diuresis 
was produced even by small doses, and the digestive tract was, as a rule, 
unaffected. They found further that the temperature, the circulatory, 
respiratory, and the nervous systems were not affected in any constant 
manner either in the dog or the guinea-pig. , 
These observers did not regard potassium once tani as toxic. They 
were also of the opinion that the ferrocyanide was transformed in the body 
to ferricyanide of potassium, and that in the guinea-pig it was eliminated in 
the urine entirely in this changed form, provided the dose did not exceed 
45 centigrammes per kilo. of body weight, but that with a greater amount 
the power to transform the salt was lost, and ferrocyanide was then 
present in the urine. They held that the condensation of the ferrocyanide | 
molecule took place probably in the blood, and, since ferricyanide of 
potassium did not cause diuresis in guinea-pigs, that the occurrence of 
this was due to the two atoms of potassium thus set free, forming salts 
of known diuretic action. They found the ferricyanide present in the 
urine as early as 45 minutes after the ingestion of the salt and in the 
third micturition, and in another case the urine gave the ferricyanide 
* Combemale et Dubiquet, ‘Compt. Rend. Soc. Biol.,’ 1890, vol. 42. 
