In examining stained blood films we have frequently observed necrobiotic changes in the white cells. These changes have been referred to by different authors. Cabot (1) writes, “frequently in leukæmia and occasionally in other conditions one sees leucocytes apparently moribund. That they are not always artifacts is shown by the fact that in normal blood they do not appear when treated by the same technique, that reveals them in the blood and hardened clot of leukæmic cases, as well as by the fact that Botkin and others have produced similar appearances by keeping the leucocytes a few days in an aseptic state.”