746 POPULAR SCIENCE MONTHLY. 



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 cer- 

 ebral 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 under- 

 supply 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 func- 

 tions 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. Sec- 

 ondarily almost any affections, even surgical diseases, may supervene, 

 caused by the lowered nutrition, disordered blood-supply or the de- 

 routed nerve influences. The terminal diseases, as they are called, 

 because they perform the final act of killing, are often but the execu- 

 tioners 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 : 



Many school children who appear dull and inattentive, who are nervous, 

 irritable, morose or disorderly, who suffer from headache, dizziness, nausea or 



