I'.U TI1K \KHV(l> SYSTEM AM) ITS C< )\SKKVAT1ON 



of nitio<ienou> foods (meat-, eggs and legumes). Bui ii 

 may develop also when the did is scanty, for it lias become 

 deal- in recent times tliat underfeeding may so enfeeble 

 the read ions of the organs of digestion that they do not 

 care for the food so well as they would for a larger and 

 more stimulating ration. 



Auto-intoxication is frequently associated with anemia, 

 and this condition a diminution of the oxygen-carrying 

 substance in the blood always threatens injury to the 

 nervou-s system. It implies limited endurance in every 

 pursuit. .lust how the anemia of auto-intoxication is 

 caused is not always plain. In some cases it is probably 

 due to the continuous formation in the intestine of a 

 poi<on which is destructive to the red corpuscles. 



Among the bodily sources of nervous damage we do well 

 to emphasixe eye-strain. Attention has already been 

 called to the primacy of the eye among the receptors 

 through which the organism is stimulated. It follows 

 that excessive use of the eyes or their employment under 

 difficulties must be harmful in a high degree. A Little 

 space may be here devoted to a comparison of the common 

 visual defects as causes of central trouble. The normal 

 eye may be abused as by reading with poor light or in 

 situations where there is vibration (in the car-) but it is 

 of special importance to discuss the near-sighted, the far- 

 sighted, and the astigmatic conditions. 



Near-sight is a defect ordinarily referable to too great 

 depth of the eyeball. The d'l'ed upon the retinal image 

 is the same that is produced in a camera when the dis- 

 tance between the len- and the plate is made greater than 

 it should be for landscape work. The distant view be- 

 comes blurred and indistinct, while objects at short range 

 are sharply defined. So in the near-sighted eye no clear 

 picture of the distance is obtainable, but things close 

 l>v are -ecu \\ith a minimum of effort. What is called the 

 normal eye is used without strain for observing things at a 

 distance, and applied to near work with a certain sustained 

 contraction of what is known as the accommodation 



