Sepp takes from the work of others certain anatomic observations, viz.: The first unique thing about the structure of brain vessels is the structure of the capillaries. Ranvier saw a double wall to brain capillaries, and Evensen proved the presence of a nonfenestrated elastic membrane in the capillaries of the brain. Sepp says that in Bielschowsky preparations a structureless membrane is visible, which folds in an irregular way when the wall of the artery shrinks. Over these lie many fibers going in different directions, which come from the "feet" of the glia about the vessel.
From the anatomic standpoint, these observations are doubtful. Is there any good evidence that the capillaries of the brain are different from those of other organs of the body? The fact that some observers state that Weigert's resorcinfuchsin stain shows a fine dark line is not sure evidence of the presence of an impermeable