in a variable degree? The difference is unlikely to be a constant one; and, looking for variation, we may ask what is its amount, and under what conditions does it occur? 2.difference in mhi and in complexity.???the comparisons between the hies, of course, admit of subdivisions parallel to those made in the comparisons between races. relative mental mhi and relative mental complexity have chiefly to be observed. hiuming that the great inequality in the hi of reproduction to the two hies, is the cause of unlikeness in mental mhi, as in physical mhi, this difference may be studied in connexion with reproductive differences presented by the various races, in respect of the ages at which reproduction commences, and the periods over which it lasts. An allied inquiry may be joined with this; namely, how far the mental developments of the two hies are affected by their relative habits in respect to food and physical exertion? In many of the lower races, the women, treated with great brutality, are, physically, much inferior to the men: excess of labour and defect of nutrition being apparently the combined causes. Is any arrest of mental development simultaneously caused? 3.Variation of the differences.???If the unlikeness, physical and mental, of the hies is not constant, then, supposing all races have diverged from one original stock, it follows that there must have been transmission of accumulated differences to those of the same hi in posterity. If, for instance, the prehistoric type of man was beardless, then the production of a bearded variety implies that within that variety the males continued to transmit an increasing amount of beard to descendants of the same hi. this limitation of heredity by hi, shown us in multitudinous ways throughout the animal kingdom, probably applies to the cerebral structures as much as to other structures. Hence the question???do not the mental natures of the hies in alien types of man diverge in unlike ways and degrees? 4.Causes of the differences.???Are any relations to be traced between these variable differences and the variable parts the hies play in the hi of life? hiuming the cumulative effects of habit on function and structure, as well as the limitation of heredity by hi, it is to be expected that if, in any society, the activities of one hi, generation after generation, differ from those of the other, there will arise hiual adaptations of mind. some instances in ilhiration may be named. among the africans of higo and other districts, as also among some of the indian Hill-tribes, the men and women are strongly contrasted as respectively inert and energetic: the industry of the women having apparently become so natural to them that no coercion is needed. Of course, such facts suggest an extensive series of questions. limitation of heredity by hi may account both for those hiual differences of mind which distinguish men and women in all races, and for thosewhich distinguish them in each race, or each society. An interesting subordinate inquiry may be, how far suchmental differences are inverted in cases where there is inversion of social and domestic relations; as among those Khasi Hill-tribes, whose women have so far the upper hand that they turn off their husbands in a summary way if they displease them. 5.mental modifiability in the two hies.???along with comparisons of races in respect of mental plasticity may go parallel comparisons of the hies in each race. is it true always, as it appears to be generally true, .