The excerpt represents the core issue or deciding factor on which you must meditate, and is drawn from A Book of Remarkable Criminals by H. B. Irving: grains of tartar emetic, which he wanted to mix in a wash
according to a prescription of Dr. Castaing. But he did not tell
the chemist that he was Dr. Castaing himself. An hour later Cas-
taing arrived at the shop of another chemist, Chevalier, with
whom he had already some acquaintance; he had bought acetate of
morphia from him some months before, and had discussed with him
then the effects of vegetable poisons. On this particular
morning he bought of his assistant thirty-six grains of acetate
of morphia, paying, as a medical man, three francs fifty centimes
for it instead of the usual price of four francs. Later in the
morning Castaing returned to Saint Cloud, a distance of ten miles
 A Book of Remarkable Criminals |