diseases are so varied, differing almost in each individual, that it is impossible to set them forth in detail. Primarily it seems certain that the process is essentially one of waste and exhaustion of nervous force; all corporeal activities depend upon right-seeing. All subordinate cerebral centers are drawn upon to restore the balance when clear and easy seeing drains too severely the optical store-houses and regulating mechanisms. But the peculiarity of nervous action is that often undersupply and even exhaustion ends in irritation and excessive nerve action. Hence we find hyperesthesia attending or consequent upon lowered vitalities and tensions. But at least and always come disordered functions and these naturally form two types or proceed by two routes. The first disorders, often the more distinctive cerebral incoordinations, are those classed as nutritional or digestional. Certainly one half of all sufferers from eyestrain have dyspepsia of some kind. 'Liver,' 'stomach,' loss of digestive power, loss or fickleness of appetite, are the complaints that constantly occur in the biographies of great literary workers, and of the majority of our patients.
The second class comprises those whose blood-supply and tension is morbidized—the so-called 'vasomotor' cases. Skin-affections, as was long ago found, are often due to 'migraine,' and migraine, we now know, is due to eyestrain. It is remarkable how often diseases of the kidneys have been preceded by years of suffering from eyestrain. Secondarily almost any affections, even surgical diseases, may supervene, caused by the lowered nutrition, disordered blood-supply or the derouted nerve influences. The terminal diseases, as they are called, because they perform the final act of killing, are often but the executioners of long precedent eyestrain. Even the infectious diseases find their best soil—and soil is as important as seed—in the lowered vitality following years of headache, dyspepsia, etc. By careful count and trustworthy statistics 27 per cent, of school children have lateral spinal curvature. This astounding source of sickness and invalidism, directly or indirectly, is due to ocular defects, functions and laws.
And if the child is father to the man, let us add, and to the woman, what a havoc of the future generation we have been preparing by our neglect of the care of children's eyes! Take it only in the aspect of a saving of time. The results of Dr. Baker's examination of the eyes of the Cleveland, Ohio, school children show that those with defective eyes are six or seven months older than the others of the same grade and that one in four have eyes that keep them behind in their studies. In the last few years the examination of the eyes and health of school children shows an appalling condition which fully bears out all that oculists have been warning against. The examiners in Quincy, Mass., state:
