TIIK \K!;V(H S S^STK.M AND ITS CONSKKVAT1OX 



need not l)c >et forth; the word "ast igmat ism" means 

 literally "not pointedness." and the reference is to the fact 

 that with such eurvatures a point outside can never be 

 imaged as a point upon the retina. Vision can never be 

 satisfactory, but at a given moment certain linear features 

 of the scene will be clearer than others which have a dif- 

 ferent direction. The attempt to change the degree of 

 accommodation so as to have a better definition for the 

 second set of lines results in sacrificing the sharpness of the 

 first. Hence, there is a restless flutter of the accommoda- 

 tion mechanism, a perpetual attempt to gain a compre- 

 hensive view, which is destined always to be baffled. 



The effects of common astigmatism upon health are 

 much like those of far-sight. The glasses used to correct 

 the deficiency must themselves be astigmatic, but in a 

 sense opposite to that in the eyes to which they are added. 

 They must have their least curvature in the meridian in 

 which the cornea has its greatest. The mounting of such 

 len-es is evidently a matter of importance, for there is 

 only one position in which they can fulfil their purpose. 



Sound heredity, successful nutrition, and eyes free from 

 hurtful strain go far toward securing an efficient nervous 

 sy.-tein, but we have yet other factors to reckon with. 

 All bodily conditions which cause discomfort must be 

 regarded as possible sources of central injury. It is prob- 

 able, moreover, that many peripheral derangements which 

 we think we can ignore or which may even have escaped 

 our recognition, may be productive of much harm. We 

 have seen that this is true of far-sight. An eminent 

 surgeon, (!. W . ('rile, has furnished striking evidence that 

 thi- may be frequently a fact. The foundation of his 

 exposition is the body of information we pox-ess with 

 re-peel to anesthesia. 1 



When ether or chloroform is introduced into the blood 

 and carried to the brain there is an interruption of certain 

 processes in the neurons which niodilie- or destroys coil- 

 but we have no warrant for assuming that 

 l p n i-t i in Medical and SurgicalJounud, I'.no, Hxiii, MIL'. 



