POISONING BY ARSENIC. 
81 
were found dead in the morning. For the last few days of 
his life the horse had been fed upon the before-mentioned 
clover. 
REPORT ON THE ANALYSIS BY PROEESSOR TUSON. 
On the 23rd of September, 186l, I received from Mr. 
Mackinder, veterinary surgeon of Peterboro', the stomach 
and its contents, of a horse, which was supposed to have 
been poisoned. 
Having, by preliminary experiments, discovered arsenic in 
the contents of the stomach, I then adopted special analytical 
methods for confirming the presence of that poisonous agent. 
By the request of Professor Simonds, I append a descrip¬ 
tion of the special process adopted in this investigation. 
About four ounces of the contents of the stomach were 
covered with moderately strong hydrochloric acid. This 
mixture was boiled for about half an hour in an appa¬ 
ratus so arranged as to effect the condensation and return of 
the volatile matters evolved during ebullition. At the com¬ 
pletion of this process of cohobation the acid magma was 
diluted with distilled water and filtered. 
Examination of the filtered fluid by Meinsclds test. —The fil¬ 
tered fluid containing free hydrochloric acid was boiled for 
half an hour with a strip of perfectly bright copper. At the 
end of this time, the copper (which had become coated with a 
dark-gray deposit) was removed from the liquid, thorougly 
dried, placed in a dry test-tube, and heated with suitable pre¬ 
cautions. 
On examining the cool parts of the tube in which the 
coated coppex’ had been heated, a white deposit was observed, 
which, when magnified, was found to consist of highly 
characteristic octahedral crystals of arsenious acid—white 
arsenic. 
Examination of the crystalline deposit by Marsh’s test .—On 
adding some of the crystalline deposit believed to be arsenious 
acid to a mixture of zinc and dilute sulphuric acid, developing 
hydrogen, and subsequently lighting the gas as it issued from 
a jet, it (the gas) burned with a peach-coloured flame. 
By depressing pieces of cold porcelain upon this flame, 
dark, semi-metallic looking stains were obtained upon them, 
which rapidly disappeared when heated in contact with the 
air, or when they w r ere moistened by a solution of chloride of 
lime. 
Thus the presence of Arsenic was shown by ReinsclTs 
test and satisfactorily corroborated by Marsh's test. 
xxxv. 6 
