The difference between the "injured" sense in the sane and insane states we must from our view point, without essaying to bridge all the _terra incognita_ which lies between sanity and insanity, regard as largely but one of degree. And so with the underlying mental and physical states. We find the morbid ideas more fixed in the sane than in the insane, frequent repetitions of the morbid impression tending to its final organization, so to speak. We also find that the morbid idea is usually more elaborated in the insane than in the sane state, although instances of the greatest elaboration are sometimes met with, especially where the element of some external foundation is large. It is probable, however, that the elements of fixity and elaboration of the persecutory idea are after all dependent upon and in proportion to the intensity of the underlying brain and mind states. In other words, that to increase a given intensity of these states is to increase the fixity and elaborateness of the "sense of injury," is to prevent the correction of the morbid idea, until finally exploited in conduct, which is the _début_ of the insanity. Thus the relativity of insanity which has all along been maintained is clear on the line here pursued. It would be equally so in following other lines of morbid psychology. It has, though, received but little general recognition, and writers still treat insanity as an entity apart from its bearings on the average mind and its evolutionary history. The word "insanity," or "lunatic," is no doubt largely responsible for this, suggesting popularly, as it does, a distinct class of persons--a type of being as unlike ourselves as a Martian might be fancied to be. Nature or science, however, has set no line between the morbid mental manifestations which constitute sanity and those which constitute insanity, that being an arbitrary, however practical, distinction which science has had rather to descend to meet. Nothing so stands in the way of the best welfare of the insane than this abysmal ignorance which still prevails in regard to them--an ignorance which still clings to the mediæval idea of insanity, the classical portraiture, as in the pictures of Hogarth, or on the stage, or in fiction; an ignorance which is ever hearkening for the maniac's shriek or the clanking of his fetters, which recognizes nothing short of "furious madness" as sufficient ground for committing a brain-sick man to the tender therapy of the hospital ward. But those who know best tell us that the insane are very much like other people, that there is wonderfully little difference between them and ourselves; and sometimes but a slight circumstance, a mere accident of environment, determines which side of the hospital wall we shall be on. EARLY EXPERIMENTS IN AIR FLIGHT. BY M. BANET RIVET.