ing the now pallid leproma, and then collecting on a cover-glass the droplet of " leper juice " which exudes from the puncture. The juice may be spread out on the cover-glass, fixed, stained, and decolorized as for the demonstration of tubercle bacilli; or it may be examined fresh. Better preparations are obtained by making with a small scalpel a minute incision into the compressed leproma, scraping some of the tissues from the under surface of the skin, and smearing this with the juice on to the cover-glass. One must be careful to exclude the possibility of contamination with Bacillus tuberculosis, with which lepers are often infected.
If examined fresh, or if a morsel of leproma be teased up in water, the bacilli may be seen both inside and outside the cells and in active motion. Whether this motion is simply molecular, or whether it is vital, is hard to say; probably the former, for, whilst osmic acid does not stop it, it is immediately arrested by the addition of a viscid fluid, such as glycerin or albumin water.
The bacillus is found in all primary leprous deposits; in the skin leproma— where it occurs in prodigious numbers; in the meagre infiltration of the macular eruptions— where it is much more sparsely distributed; in the early stage of leprous neuritis— where, also, it is present only in small numbers; in the specific lesions of the liver, spleen, testes, lymphatic glands, and lungs— where the lesions may resemble those of tuberculosis or may be invisible to the naked eye. In the blood-vessels it has been found in the endothelium and, occasionally, free in the blood or enclosed in leucocytes. It is abundant in the purulent discharges from the nose, from ulcerating lepromata or other forms of primary leprous infiltration. It has very rarely been found in the spinal cord or in the lungs. It is doubtful if it occurs in the brain, the intestinal tract, or in the kidneys, although the latter are prone to inflammation in leprosy. It is not found in muscle, in bone, or in cartilage ; and it is not necessarily present in the secondary trophic lesions of nerve leprosy, or in secondary inflammatory effusions.
