as a whole and in its parts; but our knowledge is not yet sufficient to determine this accurately, although we easily recognise the form of skull that indicates a noble and lofty intelligence. The texture of the mass of the brain must be of extreme fineness and perfection, and consist of the purest, most concentrated, tenderest, and most excitable nerve‐substance; certainly the quantitative proportion of the white to the grey matter has a decided influence, which, however, we are also unable as yet to specify. However, the report of the _post‐mortem_ on the body of Byron(13) shows that in his case the white matter was in unusually large proportion to the grey, and also that his brain weighed six pounds. Cuvier’s brain weighed five pounds; the normal weight is three pounds. In contrast to the superior size of the brain, the spinal cord and nerves must be unusually thin. A beautifully arched, high and broad skull of thin bone must protect the brain without in any way cramping it. This whole quality of the brain and nervous system is the inheritance from the mother, to which we shall return in the following book. But it is quite insufficient to produce the phenomenon of genius if the inheritance from the father is not added, a lively, passionate temperament, which exhibits itself somatically as unusual energy of the heart, and consequently of the circulation of the blood, especially towards the head. For, in the first place, that turgescence peculiar to the brain on account of which it presses against its walls is increased by this; therefore it forces itself out of any opening in these which has been occasioned by some injury; and secondly, from the requisite strength of the heart the brain receives that internal movement different from its constant rising and sinking at every breath, which consists in a shaking of its whole mass at every pulsation of the four cerebral arteries, and the energy of which must correspond to the here increased quantity of the brain, as this movement in general is an indispensable condition of its activity. To this, therefore, small stature and especially a short neck is favourable, because by the shorter path the blood reaches the brain with more energy; and on this account great minds have seldom large bodies. Yet that shortness of the distance is not indispensable; for example, Goethe was of more than middle height. If, however, the whole condition connected with the circulation of the blood, and therefore coming from the father is wanting, the good quality of the brain coming from the mother, will at most produce a man of talent, a fine understanding, which the phlegmatic temperament thus introduced supports; but a phlegmatic genius is impossible. This condition coming from the father explains many faults of temperament described above. But, on the other hand, if this condition exists without the former, thus with an ordinarily or even badly constructed brain, it gives vivacity without