Their importance arises from the fact that in these ventricles of the right and left sides of the brain a watery fluid, effused from the blood, called serum, exists, which also extends downward along the spinal cord, and which has to do with the pressure and equilibrium of the various parts. When there is a strong pressure of blood to the brain on account of its unusual activity, especially in the activity of the emotions, the serum of the ventricles and also in the substance of the brain is absorbed, and the brain acquires a more compact texture, which is found in all persons of strong mentality, the brain being hardened by exercise, as well as the muscles. But when the action of the brain is feeble, and the blood in an impoverished condition, there is a greater tendency to the exudation of fluid; the substance of the brain is thereby softened, and serum, to the extent of one or more ounces, is frequently found in the ventricles, especially when the brain is much impaired by disease of its substance. In some cases of hydrocephalus pints of serum are effused, distending the brain and head enormously, and in many cases of insanity the ventricles and membranes of the brain are distended with serum. "Pritchard on Insanity" speaks of this distention of the ventricles, which were "very full of serum" in twenty-nine out of a hundred cases, and "in twenty-three ready to burst," and "in ten among twenty-four melancholies astonishingly distended." Dr. Spurzheim dissected a case of hydrocephalus, child of eighteen months, with two and a half pounds of water in the membranes of the brain; and James Cardinal, who died at the age of thirty years in London, had a pint of water in the lateral ventricles, and about nine pints between the brain and its membranes. BUSINESS DEPARTMENT. [Hand pointing right] _The first two numbers of the_ JOURNAL _were unavoidably delayed. The May number will appear in advance of the month._