believe, as explained above, that the bacilli lie almost exclusively in the cells, the question arises whether the cells digest the bacilli, or not. As we often find cells with only one or two bacilli, and as we find in most cells balls or clumps of bacilli, we must admit that the bacilli multiply in the cells. In some cells the bacilli remain lying in separate collections, in others they fill the entire cell body, but they never penetrate into the nucleus. Finally, the bacilli break down into small granules, and this breaking down corresponds, according to our view, to a degeneration of the bacilli. Unna and Lütz have indeed stated that this granular appearance of the bacilli is constant, and is a mark of their structure, that they really consist of small rows of cocci, and Unna has therefore described them as coccothrix. This actual (!) structure of the bacilli, however, only becomes evident under the action of free iodine. But we have seen in our preparations, however they were treated, _smooth and granular bacilli lying close to each other_, and we cannot, therefore, corroborate the view of Unna and Lütz. Neisser first drew attention to clear spaces in the bacilli; these Neisser regards as spores; we regard them as the first sign of breaking down of the bacilli into granules, and for the following reasons. We have made numerous attempts to cultivate the bacilli, and have attained in all our investigations only (the breaking down of the bacilli into) granules, and in examining a piece of a nodule which lay eight days on broth peptone agar, found all the bacilli beset with clear spaces. And as the result has always been the breaking down into granules, we believe we are right in regarding the appearance of these holes as the commencement of degeneration, and that we are not as yet familiar with spores of the lepra bacillus. It appears as if all bacilli in time break down into granules, particularly in the internal organs, where it occurs much earlier than in the skin nodules; whether this is the result of digestion on the part of the cell, we cannot say; but as the bacilli at first multiply in the cells, and the breaking down appears most definitely and freely when the cells are crammed full of bacilli, it is equally possible that it is the result of diminished nutrition, and as they break down more rapidly in the internal organs, it is also possible, indeed probable, that the higher temperature in these organs favours this disintegration. As we have unfortunately not been able to cultivate the bacilli, it is at present impossible to form a conclusion. At all events, we regard the transformation into granules as a degeneration, and believe that the bacilli thus altered are dead.