Working at the Breaking Strain.

The same principle applies in the case of the heart, the liver, the lungs, and all other organs. No instance can be adduced, so far as I am aware, in which some form of retribution does not follow any disregard of Nature's intention as to keeping the stress habitually placed on any organ far below the breaking strain. In individual cases the damage done may not be detected, but I am confident that no one can point to any habitual disregard of the fundamental laws of our being which is not visited with penalties more or less proportionate to the degree of departure. This is true even of mature structures, and the harm done invariably tends to be much greater in the case of growing organs, because overwork or any other inimical factor directly checks growth and development not only of the overworked parts, but also of the organism as a whole. This is clearly seen in the case of such adverse factors as drinking, smoking, epilepsy, sexual vice, etc., which one and all tend to stunt the individual and to cause more or less defect, if present before or during puberty, though they may not cause any obvious impairment of the organism if mature at the time of onset. All these influences tell most ruinously on the growing brain and nervous system, for the simple reason that the resistiveness and the nutritive and formative activities of cells diminish as we ascend in the scale of development, and as the functions of cells become higher and more specialised. Mere protective surface cells of the skin will live for a considerable time after removal from the body, and may even be transplanted from one species of animal to another; glandular cells, standing higher in function, die rapidly if removed, have little power of reproduction, and can scarcely be transplanted. Hence struc- page 34 tural damage in the case of liver or kidney is, properly speaking, irreparable, although there may be enough sound tissue left for ordinary working purposes. The higher brain cells are extraordinarily sensitive, delicate, and complex; they are affected by the slightest variations in the quantity "and quality of the blood supply; respond to unimaginably faint impressions coming from within or derived through the senses from the outside world; have very little primitive vitality and no reproductive power; are easily over strained and thrown out of function, and when so damaged tend to recover imperfectly, or at best recuperate slowly. These cells stand at the head of the organism, in the relationship of the generals to an army—or in the position of a central bureau in relation to an infinitely complex and extended telephone system—so that failure in them involves in a lesser or greater degree the whole organism. Every part of the body has direct or indirect connection and organic relationship with the brain, and is directly or secondarily affected by what may be going on there. The arrest of digestion and nutrition which may ensue on the opening of a black-edged envelope at dinner is an illustration of the normal dependence of every bodily function on the integrity of the brain. In an instant we may have the appetite paralysed, and a flood of tears replacing the flow of secretions concerned in nutrition. Nothing can be more striking than such sudden cessation of function in distant nerve centres presiding over processes concerned in material growth and repair, and the simultaneous throwing into intense activity of centres concerned in one of the expressions of painful emotion. The analogy between this and the arrest or disturbance of certain functions in growing girls, brought about by faulty conditions of education, is obvious; and if the records of such a specialist as Dr Batchelor were immediately available they would afford illustrations within his sphere of work confirming the lesson conveyed by Dr Ferguson's statistics regarding asthenopia. Moreover, there is not a doctor in the colony who could not at once point to similar eases occurring in the course of ordinary practice. The fact is that the various functions of the nervous system are being broken down in detail in every direction by the neglect of open-air exercise, sun-light, and healthy recreation, coupled with the overtaxing of certain restricted areas of the mind. As physicians, knowing the infinitely delicate structure and functions of the brain and nervous system, it would be difficult for us to imagine a priori that the results could be otherwise, seeing how much care we have to bestow on preveting the overtaxing of the comparatively coarse and simple peripheral organs which cam on the mere drudgery of our bodies.