Anthrax

Anthrax, a word sometimes used as synonymous with carbuncle, its etymological signification, a live coal, rendering it an apt description of the pain and other phenomena attendant upon certain local inflammations. Recent observations have, however, conclusively shown that the splenic fever of cattle, and what is known as woolsorter's disease in man, are closely-related diseases; both being, in fact, due to the invasion of the body by a living organism of microscopic size, which possesses the power of excessively rapid multiplication under suitable conditions; and anthrax is now by universal consent the name given to the disease produced by this organism. In man the disease is commonly acquired by inoculation of a scratch or other abraded surface from the skins of animals which have died of anthrax; inflammation is set up at the seat of injury, and what used to be called a malignant pustule is produced. Sometimes, however, there is no skin lesion discoverable, and to this class of cases the term internal anthrax is applied.

Splenic fever in cattle is a disease of much more frequent occurrence than human anthrax. It is so called from the great enlargement of the spleen which is observed in animals dying from the disease. Horses, cattle, and sheep are all affected, and such is the loss occasioned by an epidemic, that a system of protective inoculation, devised by Pasteur, has been largely adopted in France.

Great interest attaches to the micro-organism which is the cause of the disease, the bacillus anthracis as it is called. It afforded the first example of an epidemic disease being proved to be caused by a bacterial parasite. The anthrax bacilli are very minute, 200,000 of them arranged end to end would only form a line of about three feet in length; each bacillus is about five times as long as it is broad. The blood of animals dying of anthrax teems with these minute rods, a single drop may contain millions of them, each rod being capable of vegetating in a suitable soil. The bacilli themselves are readily destroyed by certain agents, but unfortunately they possess the power of forming spores, minute egg-shaped bodies, which offer much greater resistance to mechanical injury, drying, heat, and chemical agents. These spores may retain their vitality for months and form a ready means of setting up further infection.