THE OPHTHALMOSCOPE. 



577 



The circumstances in which the pupils are found to be dilated 

 are equally important from a practical point of view, namely : 



1. In the dark or with insensitive retinae. 



2. Irritation of the cervical sympathetic. 



3. Under the influence of atropin, daturin, etc. 



4. In asphyxia or dyspnoea from venosity of the blood. 



5. Painful sensations from the skin, etc. 



THE OPHTHALMOSCOPE. 



When we look into the eye the pupil appears quite black, be- 

 cause the illumination of the eye-chamber is not sufficient to show 



Ophthalmoscopic view of fundus of eye, in which the central artery (g 

 and c) and the corresponding veins (h and d) are seen coursing through the 

 retina from the optic disk (A). 



its parts from the outside, when the light is strong. In the same 

 way when we try to look into a room in the daytime through the 

 window, we see nothing in the depth of the room, because the light 

 outside is so much stronger than that within the room. If, how- 

 ever, we look in at night, when the room is lighted up while it is 



