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In the "Transactions of the American Microscopical Society," Vol. xx, Dr. A. Mansfield Holmes of Denver publishes some experiments made at Manitou, Colo., and the summit of Pike's Peak, on the effect of sudden changes of altitude on the number of red blood-corpuscles. Similar observations made hitherto have been as a rule under conditions requiring the lapse of a considerable period of time between the blood-counts at the different altitudes. The immediate effects were therefore less assured, but at Pike's Peak the railroad afforded the means for a very rapid change of altitude of nearly 8000 feet. He found that the ascent caused at once an increase of 11.5 per cent, of the red corpuscles, which had increased, three hours later, while still on the mountain top, to 14.42 per cent. The descent in the evening was accompanied by a decrease of 9.56 per cent., though still over 4 per
HIGH ALTITUDES AND THE BLOOD-COUNT.. JAMA. 1899;XXXIII(10):612. doi:10.1001/jama.1899.02450620050011