nobody doubted his accuracy.

Archibald Mackenzie, who all this time knew, or at least suspected the
truth, held himself in cunning silence. The preceding evening he, for
want of something to do, had strolled into the laboratory, and, with the
pure curiosity of idleness, peeped into the presses, and took the
stoppers out of several of the bottles. Dr. Campbell happened to come in,
and carelessly asked him if he had been looking in the presses; to which
question Archibald, though with scarcely any motive for telling a
falsehood, immediately replied in the negative. As the doctor turned his
head, Archibald put aside a bottle, which he had just before taken out of
the press; and, fearing that the noise of replacing the glass stopper
would betray him, he slipped it into his waistcoat pocket. How much
useless cunning! All this transaction was now fully present to
Archibald's memory: and he was well convinced that Henry had not seen the
bottle when he afterwards went to lock the presses; that the cat had
thrown it down; and that this was the cause of all the yelling that
disturbed the house. Archibald, however, kept his lips fast closed; he
had told one falsehood; he dreaded to have it discovered; and he hoped
the blame of the whole affair would rest upon Forester. At length the
animal flew with diminished fury at the door; its screams became feebler
and feebler, till, at last, they totally ceased. There was silence: Dr.
Campbell opened the door: the cat was seen stretched upon the ground,
apparently lifeless. As Forester looked nearer at the poor animal, he saw
a twitching motion in one of its hind legs; Dr. Campbell said, that it
was the convulsion of death. Forester was just going to lift up his cat,
when his friend Henry stopped his hand, telling him, that he would burn
himself, if he touched it. The hair and flesh of the cat on one side were
burnt away, quite to the bone. Henry pointed to the broken bottle, which,
he said, had contained vitriolic acid.