Ch. XVIII.] moon-blindness. 309 



have not the slightest reason to suspect, they go far to 

 prove the reality of moon-blindness. 



In this case the lad was 18 years of age, of fair com- 

 plexion, full face, and large, light, greyish-blue eyes, which 

 attracted attention from their remarkable appearance. His 

 hair and eyelashes were darker however than the colour of 

 his eyes would lead one to expect. In February, 1864, on 

 a certain night about the time of full-moon, this lad was 

 sleeping on the forecastle with his face turned upward, fully 

 exposed to the direct rays of the moon. The circumstance 

 was remarked by his messmates, who remonstrated with 

 him, and assured him that he would feel bad effects from it ; 

 but in spite of these remonstrances he persisted in keeping 

 his place. Nothing ocaurred that night, but on the follow- 

 ing night he was one of a deep-sea sounding party, and was 

 beating the line, when the moon rose, and as it did so he 

 suddenly exclaimed that he could not see, and would have 

 fallen overboard if he had not been stopped as he was deli- 

 berately walking into the sea. For ten nights after this 

 occurrence, as soon as the moon rose above the horizon, he 

 complained that a cloud seemed to develop itself before his 

 eyes, and he forthwith became temporarily blind, so that it 

 became necessary to lead him about the deck ; but this only 

 happened during moonlight. On two occasions he narrowly 

 escaped serious accidents from falling down a hatchway, and 

 it became necessary to place him upon the sick-list. The 

 surgeon, a gentleman of superior attainments, with whom I 

 am acquainted, examined his eyes minutely, but could de- 

 tect nothing abnormal in them. When the man was between 

 decks, and out of the moonlight, he had no difficulty in 

 distiaguishiag objects; nor was his vision affected during 

 daylight, nor after dark before the moon rose. Ultimately 



