288 



Scientific Proceedings (129) 



139 (2099) 



The presence of anti-ophthalmic vitamin and the absence of 

 anti-richitic vitamin in dried spinach. 



By J. F. McCLENDON and CECILIA SHUCK. 



[From the Laboratory of Physiological Chemistry, University of 

 Minnesota, Minneapolis, Minnesota.] 



Steenbock has noted the decrease or disappearance of the 

 anti-rachitic substances in leaves, and MacCollum has dis- 

 tinguished between the anti-rachitic and the anti-ophthalmic 

 vitamin A. Experiments on spinach have covered a period of 

 two years and at the beginning of this period the dietary in- 

 gredients were procured in large quantities and stored in the 

 dry state in galvanized iron containers to insure uniformity of 

 product covering all of these experiments. Changes might take 

 place due to ageing, but the experience of others shows that 

 such change would be the disappearance of a vitamin and never 

 the production of a vitamin. 



In very numerous experiments spinach has demonstrated no 

 anti-rachitic property except the small effect of the phosphate 

 it contains, which is usually offset by the increased growth. It 

 is not possible to feed as much roughage to a rat as to a true 

 herbivorous animal. If 50 per cent, of the diet is made of leaves, 

 such as alfalfa meal or dried spinach, rats die in a relatively 

 short time. Spinach was fed in quantities varying from 0.01 

 per cent, to 75 per cent, of the diet and in no case was any ap- 

 preciable anti-rachitic effect noted. On the other hand, 0.1 per 

 cent, showed a definite retarding of ophthalmia (keratomalacia) 

 and a slightly greater amount was able to prevent ophthalmia 

 over a relatively long period. Very advanced cases of ophthal- 

 mia were cured in six days by feeding half a gram of spinach 

 a day. In case the lens of the eye had already popped out the 

 spinach did not cause it to go back in the eye in six days, but 

 apparently the cornea was regenerated in order to protect the 

 extruded lens and the eye assumed a healthy even though a 

 somewhat deformed condition. In case the lens had not popped 

 out of the eye, the eye in every way appeared normal after the 

 spinach diet. 



