THE DIFFERENTIATION AND SPECIFICITY OF CORRESPONDING 



PROTEINS AND OTHER VITAL SUBSTANCES IN RELATION 



TO BIOLOGICAL CLASSIFICATION AND 



ORGANIC EVOLUTION: 



THE CRYSTALLOGRAPHY OF HEMOGLOBINS. 



BY 



EDWARD TYSON REICHERT, M.D., 



Professor of Physiology in the University of Pennsylvania, 



AND 



AMOS PEASLEE BROWN, PH.D., 



Professor of Mineralogy and Geology in the University of Pennsylvania. 



