56 



MICROSCOPY OF THE LIVING EYE 



Fig, 21. — View as seen through the 

 microscope along the axis of specular 

 reflection from the posterior lens cap- 

 sule. A, when the microscope is in 

 visual focus on the plane pc, Fig. 22 ; 

 B, when focused on the level of X, 

 Fig. 22 ; C, when focused on the level 

 of d or p, Fig. 22. 



of the focusing lens (filled 

 by an image of the filament 

 of the lamp which is pro- 

 jected into this aperture) ; 

 this image, in the case of 

 each surface, lies, it may 

 ])e said verv roufrhlv, about 

 the level of the anterior 

 lens capsule. Hence, if the 

 observer sees this image in 

 focvis through his micro- 

 scope when he is trying to 

 observe the anterior corneal 

 surface bv D.I.S.R., he will 

 know that he must now 

 rack the microscope on to 

 a plane nearer himself in 

 order to bring it in focus on 

 the corneal surface which is 

 creating the mirror-image ; 

 whereas, if he is studying 

 the posterior lental surface 

 by D.I.S.R. and he sees 

 the focusing lens image he 

 must rack the microscope 

 away from himself in order 

 to focus it on the siu'face 

 which is creating the image. 

 Thus, with a small round 

 beam accurately focused 

 (illumination-focus) on to 

 the posterior lens-capsule, 

 the view of the area by 

 D.I.S.R. would be repre- 

 sented by the round patch 

 in A (Fig. 21), provided that 

 at the same time the micro- 



