DISORDERS IN RELATION TO THE EYE 755 



that of the secretion of tears under sympathetic irritation, and possibly, 

 although to a much lesser degree, the unconscious and reflex opening and 

 closing of the lid-fissure which is but one form of the wink. 



Many of the most suggestive and at the same time the most definite 

 data in endocrinology have been gained in the biological laboratory, in mor- 

 phologic experiments on lower animals, and in exact and detailed studies 

 of nutrition, basal metabolism, and growth. This is significant both for 

 the essential correctness, validity and fundamental nature of the prin- 

 ciple and for the wide field of its application in bio-physiology. On 

 the other hand this very fact indicates that much further study in a 

 different field is required before all the observations can be applied to 

 man and the clinic, to the patient in the bed, and that we have not as yet a 

 complete and ready-made formula of endocrin therapy, or, in fact, of com- 

 pletely detailed and thorough endocrin diagnosis. 



Normal development has little or nothing to do with functional ac- 

 tivity or with trophic nerve influence (Uhlenhuth). Nutrition, depending 

 on circulation and on the oxygenation, calcium and magnesium content, 

 and tonicity of the nutritive media, is the main factor. 



Biologic studies and clinical observations show a dependence of ocular 

 development on nutritional states which can be modified by diet, vitamins, 

 and endocrin extracts. Striking in the extreme case of the laboratory 

 experiment, these conditions must be mirrored, less typically and ex- 

 tremely, perhaps, in the endocrin variations within the limits of every day 

 life. Stockard has shown that merely altering the degree of oxidation of 

 the embryonic organism leads to marked developmental defects and to 

 the production of monsters controllable in detail of their variation from 

 normal. 



Acidity and alkalinity, basic biologic conditions, are important in eye 

 development, and it is at least probable that these states are connected 

 with dominance of one or the other endocrin gland or at least indicative of 

 a final dominance of one or the other of the two antagonistic systems of 

 vegetative nerve control, the vagus and the sympathetic. 



Race and Heredity. The color of the iris is a distinctive feature and 

 there is a typical eye for each race. (Nordic, Hebraic, Negroid, Mon- 

 golian, Amerind). 



The brown iris is a dominant Mendelian characteristic, suggesting 

 that dominant features, such as black hair and eyes, cataract, squint, 

 supernumerary digits, are vagotonic or chromatrotrope. 



Skull-form, dolicho-brachy-cephalic is a criterion of race. Its in- 

 fluence on the size and shape of the orbit, hypsi-conchae, chamai-conchae, 

 (Stilling) and the production of long or myopic and short or, hyperopic, 

 eyes is associated with the development of the pituitary and the spatial 

 relations to the region of the sella. Morphologic peculiarities, develop- 



