REGENERATION OF THE LENS IN DIEMYCTYLUS 401 



this wound, the upper iris was also drawn out and kept in place. 

 All animals, ten in number, were killed in from fifteen to twenty- 

 two days after operation. In case of successful operation, the 

 anterior surface as well as the edge of the upper iris fused with 

 the cornea. In four cases synechia did not occur and the lens 

 vesicle started to regenerate from the edge more or less nornlall3^ 

 In the other five specimens no typical regeneration took place 

 from the upper iris, which fused tightly by its entire surface with 

 the cornea, though the iris edge itself was rather free in these 

 cases. The reason for the absence of regeneration from the upper 

 iris edge in spite of its relative freedom is hard to ascertain, but 

 insufficient blood supply due to fusion might account for it. 



In all these five cases the lower iris presented no indication of 

 regeneration at all, except the usual slight changes. Thus it was 

 established that the lower iris is incapable of producing a lens 

 even when regeneration from the upper iris is prevented. 



Regeneration after making a. flap from the upper iris 



It is not without interest to find out where regeneration will 

 start when a flap is made from the upper iris. The iris is cut 

 above the blood vessel which encircles the pupil, together with 

 the cornea. After being stretched by pressure of the lens the 

 iris is then cut at one end and the lens extracted. The flap is then 

 pushed toward the middle of the pupil to prevent fusion. This 

 operation was done upon forty-five specimens. In a number of 

 cases regeneration occurred quite normally, probably owing to the 

 healing of the flap with the original iris. In others the flap dis- 

 appeared and the lens was formed from the shortened iris, while 

 some cases presented abnormalities as results of operation. De- 

 scription of the latter cases is given here. 



A. Twelve days after operation. The stump of the flap fused 

 with the lower iris edge, dividing the pupil into two parts. At the 

 fused part the flap is thick and irregular in its cell arrangement 

 and some of these cells show distinct depigmentation, but there 

 is no sign of regular regeneration. Depigmentation is not seen at 

 the lower iris. The upper iris is thick and the pigment-free part 



