In the course of an epidemic of measles during the winter of 1922, Bleyer of St. Louis had 264 patients under his care. These included children seen at institutions and in private practice. The epidemic was considered mild in character. All the children observed were under 12 years of age, and the majority under 7.
Bleyer made the unexpected discovery that with the onset of the eruption, the spleen became abruptly enlarged and that this enlargement just as promptly receded with the disappearance of the rash. On the day preceding the eruption, only 2 per cent of the spleens were palpable, and this figure mounted to 24 per cent on the first day of the rash and to 43 per cent on the second day, reaching the peak on the third and fourth days when the incidence of enlargement was 56 and 52 per cent, respectively. On the fifth and