The following notes on epizootic plague in rats are published in the belief that they may prove of interest to other workers.
It will be observed that the relative merits of the microscopic and naked-eye methods of detecting plague in rats have been thoroughly tested. Our data are drawn from the microscopic and anatomic appearances of 14,184 rodents examined between Sept. 13, 1907, and Jan. 14, 1908. We agree with the last Indian Commission1 in their belief that the naked-eye method alone furnishes enough data to pass on a rat as being plague infected or not. Like them, however, we preferred to combine the two methods first in order to rule out any fallacies which might be introduced by unknown local conditions. So far no disease of rats has been encountered which could possibly cause confusion, with the exception of a few instances which will be cited below under
WHERRY WB, WALKER A, HOWELL EH. PLAGUE AMONG RATS IN SAN FRANCISCO.. JAMA. 1908;L(15):1165–1167. doi:10.1001/jama.1908.25310410005001b