Upon the experimental exchange of skin transplants between normal and albinous larvæ

If sufficient speed is exercised, an exchange of the middorsal area of skin can be successfully accomplished between two frog larvæ, a normal one and its albinous mate. Since there are striking and constant differences between two such larvæ as concerns both classes of superficial pigment cells, a highly interesting opportunity to test the influence on such cells of a new host was presented. Four such successful skin exchanges were accomplished and in all instances definite and constant changes in the condition of the xantholeucophores were produced as a result of the exchange. The changes, which are well under way in an hour after such an experiment and which have yielded harmonious results, would appear to be of great value in the interpretation of the change in the physiological state of these cells which albinism produces. It will be recalled that the corial xantholeucophores in hypophysis-free albinos present a greatly expanded condition and that this expanded condition is not amenable to most experimental influences (temperature and light) although anesthetics affect it. An exactly opposite physiological state of these cells, i. e., a contracted condition, usually occurs in the normal larvæ. Successful skin exchanges altered the state of the xantholeucophores to correspond to that characterizing the new host. The change is usually observable within fifteen minutes and is invariably complete within four hours. Inasmuch as the change is much more pronounced than that exhibited by animals of weakened vitality or immediately after death, it can hardly be referable to merely a transient condition of weakened vitality. More especially is this the case, since the changes taking place terminate only when the state of the transplanted xantholeucophores fully corresponds to that characterizing the new host.