406 CHIKANOSUKE OGAWA 



A. Nineteen days after operation (fig. 3). What was unsuc- 

 cessful in the former experiment, was achieved in this case. The 

 transplanted iris piece is located in the anterior chamber near the 

 lower iris edge, instead of being attached to the retina. The lens 

 vesicle was formed anteriorly from the piece. The vesicle is 

 elliptical. The cells are pigment-free, partly cuboidal, partly 

 columnar, and arranged regularly in a simple layer. It is con- 

 nected by a stalk with the iris piece. From the upper iris there 

 is regular lens regeneration. 



B. Twenty-two days after operation. The transplanted iris 

 piece rests upon the lower part of the retina, which consists here 

 of only two layers (inner reticluar and outer nuclear). This is 

 regenerated retina. The piece presents a round cell mass, amidst 

 which there is a small vesicle, surrounded by a single layer of 

 cuboidal pigment-free cells. Mitosis is seen in these cells. This 

 structure must be considered as an early stage of a regenerating 

 lens vesicle. It is somewhat striking that the vesicle was formed 

 amidst the cell mass of the piece, while it usually starts from the 

 periphery. 



C. Twenty-two days after operation (fig. 4). The iris piece, 

 resting on the retina, forms a round cell mass, measuring 17 m 

 in diameter. In the center a cavity is formed, which is partly 

 filled with cells continuous with the wall. The wall consists of 

 one or two layers of cuboidal or columnar cells. Some of them 

 are pigment-free and show mitosis. This also should be con- 

 sidered as a iens vesicle. 



D. Twenty-four days after operation. The iris piece, trans- 

 planted into the retina, consists of two parts, pigment-containing 

 and pigment-free. In the latter there is a vesicle consisting of 

 cuboidal or columnar pigment-free cells. The cavity of the ves- 

 icle is small. Although this is imperfect, it also can be considered 

 as a lens vesicle. 



From the above it is seen that when pieces of iris are trans- 

 planted to the retina, they regenerate far better than in the eye 

 cavity. Of course in all these cases regeneration remains, as 

 might be expected, incomplete and does not attain even the 

 stage of formation of lens fibers, but the structures formed are 



