This paper briefly reviews the status of the splenic index in malaria and presents evidence which indicates that the small palpable-on-inspiration spleens of Darling have a useful significance. The technique of spleen palpation is discussed, and the results of numerous surveys by the author are presented to show a definite relationship between the small spleens and malaria. The results of some examinations of tuberculous children are given to show that they do not have more than a normal splenic index. There are also given the results of spleen palpations in Brookline, Massachusetts, where malaria does not occur. These examinations indicated that palpable-on-inspiration spleens are uncommon in non-malarious children. They also indicated that perhaps scarlet fever may leave a small palpable spleen in some 15 per cent of the cases.