After a longer or shorter period the typical picture of the maculo-anæsthetic form develops; the spots either appear stealthily or they may appear all at once with marked fever. Several forms of the eruption are described by investigators; in our patients usually only the erythematous and the yellowish or brownish pigmented ones have been noted. Usually both forms are seen on the same patient, for the simple erythematous spots become in time more and more pigmented--usually only at the periphery, where a bluish-red play of colours is often seen. Those eruptions which are all along pigmented and which develop very gradually, we have particularly noted in the intercostal spaces. Various forms--round, oval, gyrate--have been observed. The patches may be perfectly flat, or slightly elevated. The size varies from that of a pea up to that of the palm of the hand, and they may be even larger. At the commencement, we have usually found these patches hyperæsthetic; anæsthesia is only found in the older patches. They do not always at once attain their full size; we can often observe their growth; one may run into another, and then the initial form is lost. The number and extent of these patches are very varied; some patients present great map-like eruptions on the face, back and extremities; in others the patches are few and scattered. The seat of these patches corresponds in general to that of the nodules, but the back and the intercostal spaces are frequently the seat of patches, while on these areas nodules are only rarely, if ever, present. _Plate IV_ gives a good picture of the patches in the maculo-anæsthetic form--duration, two years. The white centres and the slightly elevated reddish edges are very well shown. A symmetrical distribution of the patches strikes one, and has been regarded as indicative of a central localisation of the leprous poisons of which the patches are a tropho-neurotic vaso-motor symptom; but in many cases there is absolutely no symmetry, and the discovery of bacilli in the patches themselves proves them to be the direct result of the action of the lepra poison. The lymphatic glands corresponding to the position of the patches are always swollen, and the swelling may persist long after the disappearance of the patches. The duration is very varied; some are gone in a few days or even less, others may last for years. Pigmentation of the periphery and pallor of the centre indicate that the patch is already old, and the pallid centre is always anæsthetic, the anæsthesia affecting all, or only some perceptions. The signs which Hillis indicated, as diagnostic of the patches of the anæsthetic from those of the tuberous form, we cannot recognise. The patches of the tuberous form are certainly usually thicker, indicating a greater degree of infiltration, than the anæsthetic; but as both are caused by the lepra bacillus it is evident that they may be absolutely similar. [Illustration: PLATE IV.]