As Danielssen and Boeck had described a leprous affection of the intestine, we gave great attention to this point, and as we were at the same time engaged in an investigation on the pathological anatomy of the lymphatic glands, we lost no opportunity of carefully examining these organs. It was during this investigation that we discovered the characteristic leprous affection of lymph glands, and had our attention first directed to the leprous affection of the liver and spleen, which affections are, macroscopically, so little evident, that we at first overlooked them. The leprous and tuberculous affections of the lymph glands are macroscopically so very different, that it is impossible to confuse them, and the microscopical differences are still more evident. Both fresh and hardened preparations were always examined. And since the lymph glands are always affected with leprosy, if the organs which drain into them are affected, even if this affection is very slightly developed, we conclude from the fact that we have never seen a leprous bronchial or mesenteric gland, that there is no leprous affection of the lungs or of the intestine, and later examination of certain special preparations have only confirmed us in this view. But more of this later, and we will first treat of the differences between tuberculosis and leprosy. In organs affected with tubercle one always finds, as is well known, giant cells and caseous degeneration; in the many, we can truthfully say, thousands of preparations of leprous affections, which we have had under the microscope, we have never seen either a typical giant cell with marginal nuclei or caseous degeneration. There are indeed multinuclear cells in the lepromata, but never giant cells like those of tubercle. What may be the reason for this striking difference in the action of the very similar bacilli of tubercle and leprosy, we have no idea; we simply state the fact and assert that, if one finds giant cells, he is dealing with tuberculosis and not with leprosy. This alone would be sufficient to cause us to separate the two neoplasms, but there are many other distinctions. Tubercle is avascular; the leproma is rich in vessels; tubercle undergoes caseous degeneration, the leproma never. Anatomically therefore, we are justified in maintaining a sharp distinction between the two diseases.