Plague (Bubonic Plague— Pestilence— The Pest—Black Death).—This is a disease believed to have been observed as early as the second century before Christ. It was common- in Egypt, other parts of Africa, and Asia. In the sixth century after Christ it spread over Europe. From that time it continued to exist in Europe, breaking out at intervals in fierce epidemics. Towards the end of the seventeenth century it began to disappear from Europe, from which, however, it had not quite de parted till 1841. From 1665, the date of the Great Plague in London, the disease disap peared from Great Britain, and continued to be unknown in that country till 1900, when it re appeared in Glasgow, but was speedily extin guished by vigorous sanitary measures, having attacked 36, of whom 16 succumbed. It seems still to exist in Arabia, Persia, and other parts of Asia. Starvation, filth, and overcrowding are the conditions that favour its spread. It is extremely contagious, and may be inhaled in dust and carried about by clothing.
Rats are very susceptible to the infection, and active agents in its propagation. The fleas which infest a sick rat, and leave it when dead, may by their bite communicate the disease to man. The infection is an organism—a bacillus,
which can be artificially reared. It is imme diately destroyed by a solution of bichloride of mercury of the strength of 1 per 1000.
Symptoms.—The disease appears about five days after infection. It begins with shivering, with fever, pain in the forehead, back, and limbs, and great weakness of body. The patient wears a dull, stupefied, haggard look. Front the second to the fourth day of the disease swellings of glands (buboes) appear at the angles of the jaws, in the armpit and groins. The eyes are red, skin hot, tongue as if covered with wool, or dry, black, and cracked. The gland swellings cause pain, and come to matter if the patient does not die before.
The majority of deaths occur within four or five days. The death-rate is not less than one in three.
Treatment is by the injection of an anti-toxin (p. 514), Yersin's, and, during an epidemic of plague, protection may be obtained by the use of liaffkine's protective inoculation.