EEGENERATION OF THE LENS IN DIEMYCTYLUS 397 



with pigment granules, appear in the space produced by the spht- 

 ting of the two layers. These round cells were considered by 

 Wolff and Miiller as leucocytes. Concerning the separation of 

 the two epithelial layers of the iris, Wolff is inclined to assume 

 that it is caused by pressure of the leucocytes which enter between 

 them. On the contrary, Fischel states as follows: "Mit einer ein- 

 fach mechanischen Erklarung kann man hier nicht auskommen 

 . . . . Die Zahl der Leukozyten ist eine zu variable und ihr 

 Durchtritt durch die Iris erfolgt in zu unregelmassiger Weise und 

 nicht an alien Stellen, um eine so gleichmassige, allseitige Abhebung 

 bewirken zu konnen." It is not justified, however, to count the 

 presence of the leucocytes as a cause of separation, because even 

 in cases where no leucocyte is visible, separation of the two layers 

 can be seen. 



Thickening as well as depigmentation increases and extends 

 from the middle part of the edge in various directions. The iris 

 edge prevents a more distinct swelling. Especially cells of the 

 inner layer increase in their height. Although the cells are ar- 

 ranged usually in a single layer in the beginning of regeneration, 

 they may consist in this stage already of two layers. As a result 

 of depigmentation, nuclei are revealed gradually in epithelial cells 

 of both layers. While Wolff, Miiller, and Fischel point out depig- 

 mentation in the inner layer, it takes place at first also in the outer 

 layer in slight degree. The split between the two layers becomes 

 more marked and extensive, and round pigment cells are to be seen 

 in the cavity. As Fischel mentioned, depigmentation and thick- 

 ening take place also in the lower iris edge in this stage and extend 

 gradually toward other regions. 



Still later, epithelial cells in the iris edge lose their pigment more 

 and more, finally becoming entirely pigment free. The same pro- 

 cess extends in the inner layer dorsally from the edge. Depig- 

 mentation in the outer layer, however, reaches only such degree 

 that the nuclei become visible in the cell bodies. Sometimes the 

 whole inner layer from the iris edge to the pars ciliaris may lose 

 its pigment, but in other cases, on the contrary, total depigmen- 

 tation is restricted to the iris edge and does not extend further,, 

 the rest of the iris containing more or less pigment all the time. 



