Tuesday, two children belonging to Mr. Fletcher, of Orcas-street, New Road, ate of some dough paste, mixed up with a quantity of arsenic, for the purpose of destroying rats, which had been carelessly left on the kitchen table by one of the servants. In a short time afterwards they complained of a painful sensation of burning in the throat and mouth, and were seized with violent vomiting and excruciating pains in the head and stomach. Medical assistance was obtained as speedily as possible, and by the operation of a powerful emetic the contents of the stomach were ejected; the poison, however, had taken such hold on the system, that both of the children's lives are considered in great danger, particularly the youngest, of whose surviving not the slightest hope can be reasonably entertained.