DISEASES OF THE LENS 141 



without removing the entire capsule at the time. Ex- 

 traction of the lens in and with the capsule is practised 

 by many operators, but with animals it would be a 

 hazardous undertaking, as it requires much time, care, 

 and special skill, besides there is greater danger of losing 

 much vitreous and possibly the eye itself. 



A capsular cataract is due to a proKferation of cells 

 .upon its surface and a thickening of the capsule, which 

 does not occur until some time after extraction. It 

 eventually diminishes the effect of the operation. In 

 hypermature cataracts this change takes place in com- 

 mon with the degeneration of the lens substance. 



In some instances a cataract will clear up spon- 

 taneously, though when it becomes complete there is 

 less probability of it doing so. In traumatic cataract, 

 when the lens is soft and the capsule is completely 

 ruptured, so that the lens substance escapes, it is usually 

 absorbed. This process of absorption sometimes takes 

 place very rapidly, even within forty-eight hours after 

 the injury. In traumatic cataract of old and hard lenses 

 this ready absorption does not take place; on the con- 

 trary, the lens remains cataractous, and often swells to 

 such a degree as to produce much increase of tension 

 and severe pain, when immediate extraction is often 

 necessary. 



In the early stages of cataract massage over the 

 closed Kds has apparently benefited some cases, while 

 in others it has seemed to create an increase in the 



