brain steadily innervate a muscle to continuous contraction. There results eyestrain—an error, the result of an error, the consequence of an older error; all may be done away with by an easily-obtained, at present usually unobtainable, device. The obtaining of that device is a matter of more importance to civilization than all the universities and wars of the last century. 'Exaggeration?' Not so!
For what are the consequences of eyestrain? Wherever there is eye-labor 'at near-range,' as in reading, writing, sewing, mechanics, art, science, commerce, etc., there, beyond question in one half the workers, is eyestrain of a disease-producing kind. What kinds of diseases?
Firstly, those of the eye itself, for surely all good oculists agree that a large majority of local eye-diseases are themselves directly or indirectly due to eyestrain. The only exceptions are albinism, loss of accommodation generally (presbyopia), some tumors and a few minor affections. Cataract, it is being recognized, is due to the morbid function of denutrition set up by the strain to neutralize errors of refraction, and may be prevented by wearing correcting spectacles long prior to the 'cataract age.' Almost all other inflammations of the eye, not excepting often the infectious ones, are usually due to the same morbid function. Function, as all good physiologists know, always precedes structure, and malfunction, as all good physicians know, also precedes the morbid and fatal organic pathology. Eyestrain is almost always the cause of eyes turning in, or out, that is, squint or strabismus, a trouble that is 'innervational in nature and refractional in origin.'
The next of the series of bad results of eyestrain are cerebral. The brain comes out to see, but owing to the enormous difficulty of the task, it sees poorly and with exhausting or irritating labor. As its every process and act is bound up with and the product of vision, visual disorders by reflex and passed-on malfunction induce cerebral affections, evidenced primarily by headache, migraine, etc. Although the medical text-books give little or no hint of this, it is true, as thousands of good physicians and patients well know, that headaches, ninety per cent, at least, are due to eyestrain. Many observant physicians believe that the so-called 'paroxysmal neuroses,' periodic headaches, migraine, epilepsy, asthma, etc., as well as hysteria, neurasthenia, 'brain-fag,' 'nervous breakdown' are very frequently caused by years of morbid ocular struggle.
Mental diseases follow: weariness, alternating with hyperexcitability, an amazing need of walking, truancy (escaping from ocular labor), morbid introspection, nameless torments and self-tormentings, diseased habits, hopelessness, melancholia, manias, incipient and functional insanities and indirectly occupational failure, crime and many other errant trends.
The methods by which morbid ocular function induce various bodily
