682 VERHOEFF AND BELL. 



not seem to hamper either animal in its judgment of distance except 

 for a short time after the left eye had been made bhnd. 



In all four experiments the magnetite arc was used and the same 

 arrangement of lenses employed as in the previous experiments with 

 rabbits, the quartz cell, as stated, being filled with a 1^% solution of 

 copper chloride. The light was focussed on the centre of the cornea. 

 The animal was placed in a box which allowed only the head to 

 protrude, and the eyelids kept open by means of a small speculum. 

 The head was forcibly held in position by the hand of the observer. 

 For the first five minutes the animal was difficult to control, but after 

 this no great difficulty was experienced in keeping the eye in place. No 

 local or general anaesthetic was employed. Normal salt solution was 

 dropped on the cornea from time to time. The pupil of the right eye 

 was previously dilated by homatropine except in the third experiment 

 in which atropine was used. 



To give some idea of the light intensity and duration of the exposures 

 in these experiments, it may be well to state that one of us exposed 

 his eye with undilated pupil to these conditions for fifteen seconds, 

 and obtained an absolute scotoma which gradually disappeared within 

 five minutes. Erythropsia persisted about three minutes and was 

 followed by xanthopsia which lasted the remainder of the five minutes. 



Experiments. 



Experiment 94. March 7, 1913. Young monkey, Macacus Rhe- 

 sus. Right eye exposed 1^ hours. Immediately after exposure there 

 is a lid reflex to a new 2| volt tungsten flash light, and within 

 five minutes the consensual pupillary reaction is apparently normal. 

 Within ten minutes the animal is able to see an apple five feet away, 

 which he approaches and takes from the hand. March 8. Cornea 

 clear. Consensual pupillary action normal. Slight direct pupillary 

 reaction in right eye in spite of mydriasis. Owing evidently to the 

 cycloplegia, the animal cannot catch flies readily. After several days, 

 the mydriasis having disappeared, the animal is able to catch flies 

 with his usual dexterity. 



Experiment 94a. March 28, 1913. Old female monkey. (Java.) 

 Right eye exposed 1| hours. Immediately after exposure the lid re- 

 flex to the flash light is absent, but is present in five minutes. Con- 

 sensual pupillary reaction not determinable owing to some of the 



