DISEASES OF THE LENS 139 



plicated with diseases of other structures. The size of 

 the pupil is not affected unless iritis or glaucoma exist. 



When a cataract occupies the pupillary area the color 

 of the pupil changes from its dense black to a bluish- 

 white or gray appearance. 



In examining the lens for incipient cataract the pupil 

 should be dilated by the use of atropin and illuminated 

 by oblique Hght or the transilluminator, when spokes in 

 the extreme border of the lens can be seen radiating 

 toward the center. They can easily be seen through a 

 strong lens by the aid of the ophthalmoscope. 



A senile cataract usually begins in this way, by 

 branching or spoke-like opacities radiating from the 

 periphery. 



As before mentioned, auto-intoxication has been 

 hinted at as a cause of this type of cataract. The lens 

 is a non-vascular body, and receives its nourishment 

 from the ciliary processes through the circumlental 

 space. It is suspended by Zinn's ligament, which not 

 only fuses with the lens capsule, but apparently dips into 

 the lens substance somewhat, producing a sort of 

 serrated condition of the peripheral portion. It is at 

 this particular point that the cataractous spokes appear 

 to arise. 



A cataract of the senile type is divided into four 

 stages— viz., incipiency, intumescence, maturity, and 

 hypermaturity or degeneration. Nothing of importance 

 is noticeable during the first stage, unless it be com- 



