“By this time a small quantity of clear liquid from the contents of the basin had passed the filter; this was removed from the glass vessel employed to receive it into a test glass, and on the application of the tests for the detection of oxalic acid not the smallest trace was indicated. I then felt quite certain that oxalic acid had not been the cause of death.
“I was then shown the stomach by Messrs. Champneys and Norblad, and on examining its interior surface it did not appear to have been acted on by any corrosive substance: nevertheless I thought it advisable to search for sulphuric acid, and accordingly applied to a small portion of the liquid, filtered from that which had been boiled, the test for that substance, but none could be detected. In like manner I did also apply the tests for the detection of baryta, opium, arsenic, the salts of mercury, and other metallic poisons, and could find none of them. I then came to the conclusion that, if the person had died from the effect of poison, it could be no other than prussic acid.
“A portion of the contents of the stomach was then taken from the bottle and put into a tubulated retort, to which was added a very small quantity of dilute sulphuric acid; the retort with its contents was placed on the sand bath, a receiver applied and a portion distilled off. When about two drachms of clear liquid had distilled over, it was removed from the receiver into a test glass, about a grain of green sulphate of iron was added, and when this was dissolved, a small quantity of solution of potassa. These were allowed to remain a short time together and stirred with a glass rod. Subsequently muriatic acid was added in sufficient quantity _when instantly Prussian blue appeared_, which could not have resulted unless cyanogen or hydrocyanic acid had been present. But it could not be recognised by the smell. Although I had no doubt in my own mind, from the gentle heat that had been employed in the above detailed process of distillation, that the prussic acid could not have resulted from any decomposition of the animal matters present in the contents of the stomach, yet I thought it prudent to conduct the process of distillation in such a manner as to preclude the possibility of such occurrence.