+Anthrax.+ This disease was one of the first in which the causal agency of bacteria was proved. In 1849 Pollender found an innumerable number of small rods in the blood of animals suffering from anthrax. In 1863 Davaine described these, and attributed the disease to them. But it was not till 1876 that Koch finally settled the matter by isolating the bacilli in pure culture and describing their biological characters. It is owing in part to its interesting bacterial history, which opened up so much new ground in this comparatively new science, that anthrax has assumed such an important place in pathology. But for other reasons, too, it claims attention. It appears to have been known in the time of Moses, and was perhaps the disease described by Homer in the First Book of the _Iliad_. Rome was visited by it in 740 B.C. Anthrax is an acute disease, affecting sheep, cattle, horses, goats, deer, and man. Cats, white rats, and Algerian sheep are immune. Swine become infected by feeding on the offal of diseased cattle (Crookshank). The _post-mortem_ signs are mainly three: The _spleen_ is greatly enlarged and congested, is friable to the touch, and contains enormous numbers of bacilli; the _skin_ may show exudations forming dark gelatinous tumours; and the _blood_ remains fluid for some time after death, is black, tar-like, contains bubbles of air, and shows other degenerative changes in the red corpuscles, whilst the _small blood-vessels_ contain such vast quantities of bacilli that they may be ruptured by them. Particularly is this true in the peripheral arteries. Many of the organs of the body show marked congestion. [Illustration: BACILLUS OF ANTHRAX AND BLOOD CORPUSCLES] [Illustration: THREADS OF BACILLUS ANTHRACIS, SHOWING SPORES]