Danielssen and Boeck have also described a mixed form of the disease, in which nodular Leprosy is combined with anæsthetic. Sometimes the skin eruption disappears and the nodular form passes into the anæsthetic, and sometimes, though much more rarely, the anæsthetic into the nodular; and since, further, the two forms are so different in their clinical appearances that they look almost like different diseases, the recognition of a mixed form might appear to be justified. But since every case of nodular Leprosy is accompanied by affection of the nerves and anæsthesia; and the natural termination of every case of nodular Leprosy is to pass into the anæsthetic form, if only, as occasionally happens, the patient live long enough; and since the skin eruptions of the maculo-anæsthetic form are characterized, just as those of the nodular form, by the presence of the leprosy bacillus, we regard the transformation of a case of maculo-anæsthetic into nodular Leprosy only as a sign of the unity of the two forms, and we delete altogether the name of mixed Leprosy. Otherwise every case of nodular Leprosy must, at all events after some years of existence, properly be called “mixed,” for in such cases anæsthesia is never absent. It has been attempted to indicate as a special form of the disease a Nervous Leprosy, in which no characteristic skin affection is present.[1] In view of what we have noted above, that nerve Leprosy is present in both forms of the disease, and that an eruption may be noted at some period in all carefully observed cases of the disease, this attempt to indicate a special nerve Leprosy is evidently wrong. [1] See Neisser: Lepra in Ziemssen’s Handbook. We will first of all discuss separately the two forms of the disease, the nodular and the maculo-anæsthetic, and then proceed to demonstrate the unity of the disease in spite of the differences in form. CHAPTER II. NODULAR LEPROSY. Nodular Leprosy (_Lepra tuberosa, L. tuberculosa_) is usually easily diagnosed by its characteristic skin affection.