EFFECTS ON THE VISUAL APPARATUS 221 



this disease. Thus retinal hemorrhages were reported by Jacobsthal ('oo). 

 Kitamura ('io) found retinal hemorrhage and edema, with circumscribed 

 hypertrophy of the nerve fiber and ganglionic layers. He also cited earlier 

 observations by Grenet, Belowsky, and Sato and Nambu, indicating the 

 occasional occurrence of conjunctival hemorrhage in scurvy. This was also 

 noted by Blake ('21). 



A weakness of vision in the form of nyctalopia (night-blindness), or more 

 rarely hemeralopia (day-blindness) has been noted during adult scurvy by 

 Zak ('17), O'Shea ('18), Bierich ('19) and others. Zak stated that in Russia 

 at Easter time, following the 7 weeks' fasting period, a visual disturbance arises, 

 termed " chicken-blindness." There are no objective symptoms, aside from 

 a conjunctival xerosis, and the disorder is easily curable by using fresh liver 

 or cod liver oil. Therefore it is apparently related to the xerophthalmia above 

 mentioned. O'Shea noted pallor of the optic disc in 3 out of 22 cases with 

 scorbutic night-blindness. Blake ('21) describes a case of exophthalmos due 

 to orbital hemorrhage in infantile scurvy, and cites similar observations by 

 previous investigators (found in 49 out of 379 cases by the collective investi- 

 gation of the American Pediatric Society). The ocular lesions in scurvy 

 are included in the recent review by Hess ('20). Bessesen ('23) found the eye- 

 balls to remain nearly constant in absolute weight, therefore appearing relatively 

 above normal on account of the loss in body weight by scorbutic guinea pigs 

 (Table 12). 



Aqueous Inanition. — A few data are available concerning the effect of 

 water deficiency (thirst) upon the visual apparatus. Schuchardt ('47) noted 

 an apparent loss of 4 per cent in the weight of the eyeballs in pigeons with loss 

 of 44 per cent in body weight on a dry barley diet. In a dog (initial age 76 days) 

 with loss of 20 per cent in body weight after 4 weeks on a diet of dry biscuit, 

 Falck and Scheffer ('54) found, in comparison with a normal control, an apparent 

 increase of 19.7 per cent in the weight of the eyeballs, with a very slight increase 

 in their water content (from 89.8 to 90.9 per cent). 



In adult albino rats on a dry diet, Kudo ('21) found that in the acute thirst 

 series, with body loss of 36 per cent, the eyeballs lose 10.2 per cent in weight; in 

 the chronic thirst series, with body loss of 52 per cent, the eyeballs lose 13.3 

 per cent; and in total inanition, with body loss of 47 per cent, the eyeballs lose 

 13.0 per cent (Table 9). Opacity of the lens apparently caused visual dis- 

 turbance in some cases; the conjunctiva sometimes appeared congested, and 

 once hemorrhagic. In young albino rats held at constant body weight for 

 various periods by a relatively dry diet, Kudo ('21a) found a progressive 

 increase in weight of the eyeballs, amounting to about 71 per cent in those on 

 the diet 9-13 weeks (Table 10). Thus during aqueous inanition the eyeballs 

 in the adult rat lose slightly; but in the young rat they increase remarkably 

 in weight, much as has been found during total inanition (Table 4). 



Pernice and Scagliosi ('95, '95a), in an adult dog which died after 9 days 

 on diet of dry bread, noted that the white of the eyes became slightly yellow; 

 and the right eye, later both eyes, developed a purluent conjunctivitis. 



