The work of eradication was at the same time commenced in all the infected States. Before the end of the year 1889 Pennsylvania, Delaware, Maryland, the District of Columbia, and Virginia had been freed from the disease. More difficulties, however, were encountered in the States of New York and New Jersey, on account of the larger territory infected and the density of the population. The long struggle was successful, however, and the last animal in which the disease appeared in the State of New York was slaughtered early in 1891, and the last one affected in New Jersey met the same fate early in the spring of 1892.