(i) Professor Keith has (1911) been much impressed with the exuberance of bone-formation, and the parts it affects in the disease known as Acromegaly. The disease seems dependent upon an excessive activity of processes regulated by a glandular body in the floor of the brain-case (the pituitary gland). The suggestion is now advanced that a comparatively slight increase in activity might result in the production of such 'Neanderthaloid' characters as massive brow-ridges and limb bones. (Of existing races, some of the aborigines of Australia would appear to exemplify this process, but to a lesser degree than the extinct type, since the aboriginal limb bones are exempt.) Professor Keith adopts the view that the Neanderthal type is ancestral to the modern types. And his argument seems to run further to the following effect: that the evolution of the modern from the Neanderthal type of man was consequent on a change in the activity of the pituitary gland. It is quite possible that the agency to be considered in the next paragraph, viz. climatic environment, may play a part in influencing pituitary and other secretions. But heavy-browed skulls (and heavy brows are distinctive tests of the glandular activity under discussion) are not confined to particular latitudes, so that there are preliminary difficulties to be overcome in the further investigation of this point. It is possible that the glandular activity occasionally assumed pathological intensity even in prehistoric times. Thus a human skull with Leontiasis ossea was discovered near Rheims at a depth of fifteen feet below the level of the surrounding surface. (ii) Dr Sera[53] (1910) has been led to pay particular attention to the remarkably flattened cranial vaulting so often mentioned in the preceding paragraphs. As a rule, this flattening has been regarded as representative of a stage in the evolution of a highly-developed type of human skull from a more lowly, in fact a more simian one. This conclusion is challenged by Dr Sera. The position adopted is that a flattened skull need not in every case owe its presence to such a condition as an early stage in evolution assigns to it. Environment, for which we may here read climatic conditions, is a possible and alternative influence.