Similar relations to those which obtain with regard to the size of the skull are found in the bodies of criminals, in respect of the size, or, rather, the weight of the brain, since the mass of the brain must naturally bear a definite relationship to the cubic capacity of the skull. In my “Naturgeschichte des Verbrechers” (“Natural History of the Criminal”), published in 1893, I have collected the data known at that period, derived, for the most part, from Italian sources; these data relate to 305 brains accurately examined. To understand the results here given, it is necessary to remember that the average weight of the European brain, the mean resultant of a very large number of weighings, is 1,360 grammes for males, and 1,220 grammes for females. A maximum very rarely exceeded (though it was exceeded, for example, in the case of Cuvier, and also in that of Tourgeniew) is a brain-weight of 1,800 grammes; whilst the smallest brain-weight known in individuals who can be regarded as having possessed normal intellectual endowments is 960 grammes for males, and 880 grammes for females. Among a very large number of normal brains, we shall find very few indeed weighing as little as 1,150 grammes, and a considerable number weighing more than 1,500 grammes. On the other hand, among the total number of the brains of criminals that have hitherto been weighed, we find that brains weighing less than 1,300 grammes form a very considerable majority; whereas, among the brains of normal individuals, less than 25 per cent. weigh less than 1,300 grammes. In the various collections of the brains of criminals, we find that brains weighing less than 1,300 grammes numbered, in one case, 62·5 per cent. (Benedikt), in a second case, 77 per cent. (Mingazzini), and in a third case, 83·2 per cent. (Mondio).