802 PERCY FRIDENBEKG 



secondary infection which may account for some at least of the serious 

 sequelae such as perforation of the cornea and panophthalmitis. The 

 factor of traumatism must also be considered. 



The lessened resistance produced by lack of fat soluble vitamin first 

 becomes apparent in many cases of rats by a characteristic infection of 

 the external eye which has been provisionally classified as xerophthalmia. 



Stephenson and Clark found invasion of the cornea by leucocytes to be 

 the first change. Later, edema and swelling of the cornea and an inter- 

 stitial keratitis were noted but they failed to demonstrate any histological 

 change in the cornea preceding bacterial invasion. Similar changes with 

 early cornification of the epithelium were reported by Freise, Goldschmidt, 

 and Frank. The nature of the pre-inflammatory lesion which produces the 

 degeneration, loss of nutrition and marked susceptibility to infection has 

 net, so far, been discovered by histological examinations and its nature can 

 only be hypothesized (Wason). The well known specificity of chloroform 

 for the liver cells, of mercury for the epithelium lining the convoluted 

 tubules of the kidney, and of tetanus toxin for the central nervous system 

 may serve as analogues. The importance of secondary bacterial invasion 

 cannot be ignored (Wason). 



The eye symptoms promptly cleared up on administration of the fat- 

 soluble vitamin in the form of butter-fat, less quickly with alfalfa oil 

 or spinach oil. 



Young animals are particularly susceptible to deficiency of fat-soluble 

 vitamin (Drummond and Coward), and in substantial harmony with this 

 is the further fact, noted by Osborne and Mendel, that ophthalmia is a rare 

 occurrence in more mature animals. 



Xerosis, essential shrinking, of the conjunctiva, has been noted in man 

 in connection with hemeralopia, or alone, in starvation states, and in 

 undernourished native children as a Brazilian ophthalmia sui generis 

 (Gama Lobo). The presence of a specific microorganism (B. xeroseos) 

 and the similarity to pemphigus indicate an infectious factor. Whether 

 this is primary or not has not been determined, but it seems probable that 

 the pathogenesis is quite analogous to that of avitamin corneal xerosis. 



It is worth noting that conjunctival instillations of milk and other ani- 

 mal fats have been followed by marked and rapid improvement in this 

 obstinate, progressive, and serious condition. 



Keratoconus is a hypothyroid manifestation, associated with lowered 

 intra-ocular tension and tonus, and lowered nutrition of the cornea. 

 Abderhalden dialysis tests applied in three cases of this condition by v. 

 Hippel, showed disturbed metabolism involving the thymus, suprarenals, 

 and thyroid. 



