It is also held by Dr. Goring that there is no such thing as a "mental criminal type." It is not denied that marked unlikeness of mental characters exists between criminal groups, as it does between different sections of the law-abiding community; but the point emphasised is that this unlikeness is associated not with a differentiation in criminal tendency, but with the criminal's differentiation in general intelligence or mental capacity, which, according to the nature of his crime, varies enormously: _e.g._, the percentage of actual mental defectives convicted of stack-firing is 53, of rape 16, of stealing 11, of manslaughter 5, whereas amongst persons convicted of embezzlement, forgery, and other forms of fraud, the percentage is practically zero. The recent Commission on the Care and Control of the Feeble-minded, from an enumeration of defectives in sixteen representative districts of the British Isles, estimated that ·46 per cent. of the whole population of England and Wales are mentally defective; a similar enumeration in prisons, casual wards, shelters, etc., revealed 10·28 per cent. of mental defects. Dr. Goring contends that it is clear from this that criminals, as well as showing wide differences amongst themselves, are also, as a class, highly differentiated in mental capacity from the law-abiding classes. Mental defectives, it is argued, unlike the insane and pathological imbeciles, are not a special class of human beings, and they are chiefly distinguished from other normal persons by their low level of general intelligence. The term mental deficiency, as applied to convicts, as well as connoting a mind of inferior capacity, in many cases implies also an unbalanced mind, _i.e._, a mind whose equilibrium is easily disturbed by the preponderance of extreme degrees of objectionable and dangerous qualities, such as impulsiveness, excitability, passionate temper, &c. These qualities are held to be not "morbid" but "natural," being shared in some degree by persons of all mental grades. The measure of general intelligence among criminals bears also a striking relation to their occupational class. Thus, if we examine, say, 1,000 cases of conviction for crime, we should find that the percentage of mentally defective criminals varied from 6 to 35, accordingly as the offender belonged to the professional, commercial, artizan, or labouring class,--the actual percentages for all crime in each class being 6, 15, 26, and 35, respectively. Probably, in the opinion of Dr. Goring, the chief source of the high relationship between weak-mindedness and crime resides in the fact that the criminal thing, which we call "criminality," and which leads to the perpetration of many, if not most, anti-social offences to-day, is not _inherent wickedness_, but natural stupidity. The striking characteristic of 90 per cent. of offences is their incredible stupidity, and, moreover, it is probable that the commonly