804 PERCY FRIDEKBEEG 



j 



of great value in ocular conditions, notably choroidal affections, in which 

 a specific luetic basis could be excluded. 



A marked individual reaction to meiotics and mydriatics is seen in 

 health and disease, and the factors of age, sex, epochs, and general con- 

 dition are well worth further study. The details of the action of these 

 alkaloids on the physiological processes and pathological conditions of the 

 eye have been studied and reported so fully by Lewin and Guillery, and 

 others, that a reference by the writer to those sources of information must 

 suffice. 



The use of adrenalin as a hemostatic and as an adjuvant to astringents 

 to reduce hyperemia in conjunctivitis and similar superficial ocular in- 

 flammations and to aid. the action of cocain as a vasoconstrictor and 

 anesthetic before ophthalmic operations is a well established procedure. 



Action on pupil. Ordinarily, adrenalin does not affect the pupil, as 

 the vagotone of the sphincter under physiological conditions is sufficient 

 to overcome any weak dilator pupillae action. Similarly, sympathetic 

 irritation under emotional stimulus will cause mydriasis only in as far as 

 there is loss of vagotone. * Thus, in glaucoma or in a tendency to patho- 

 logical plus tension, even a weak solution of adrenalin instilled while the 

 pupil is small may produce a rapid dilatation and rise of tension and 

 halo vision. The provocative instillation of cocain in weak solutions acts 

 similarly, and this is the more striking as, at the age at which glaucoma 

 is most common, there is, in normal eyes, a decided (vagotonic) resistance 

 to mydriatics, expressed in a tendency to small pupils, a certain rigidity 

 of the iris, and an intolerance to meiotics, such as eserin, which are very 

 apt to produce symptoms of iritis. In Zentmayer's resume, there is a state- 

 ment to the effect that suprarenal extract produces mydriasis when the 

 sympathetic is paralyzed, after extirpation of the thyroid, in exophthal- 

 mic goiter, and following the administration of thyroid extract. I have 

 been unable to reconcile these contradictory statements. 



Endocrin Therapy. Epinephrin. There is no reason for believing 

 that adrenalin has any effect on the intra-ocular tension of normal eyes. 

 In glaucoma, it first lowers, then raises, and finally again lowers, tension. 

 This may be secondary to the mydriatic action described above, as extreme 

 dilatation of the pupil in middle or old age is apt to find topographical 

 conditions of intra-ocular filtration which predispose to an acute attack 

 of glaucoma. Loss of the normal vagotone, which as we have seen, tends 

 to keep down intra-ocular tension, is strikingly indicated by this reaction, 

 as well. 



Seasonal Incidence. The prevalence of a disease at a certain time of 

 the year has been generally attributed to prolonged cold or heat, bad hy- 

 gienic conditions, such as overcrowding, defective ventilation, lack of food, 

 gastro-intestinal toxemia from these factors as well as from constipation, 

 and lack of exercise. The practical validity of this assumption has been 



