1922. No. 4. MIOSIS CONGENITA SEU MICROCORIA FAMILIARIS. I5 



moreover inconstant, as it was often absent in corresponding places in 

 other sections. 



This absence of the Bruch's membrane is indeed so marked as regards 

 the middle part of the iris, that it may be said to be the rule. The most 

 that is seen in these non-depigmented sections is a faint reddish colour at 

 the anterior margin of the pigmented layer between this and the stroma. 

 But in the central part of the iris, i. e. behind the sphincter, a distinct red 

 rim, answering to the membrane of Bruch in normal sections, is constantly 

 seen. It seems to me, also, that it is of about the same thickness as in 

 the control preparations, although it is impossible to judge of this accu- 

 rately by comparing microscopical sections of the eyes of various persons. 



Thus the very first general preparations I made differed considerably 

 from the ordinary descriptions of the normal iris, and the difference was 

 also very marked when I compared them with the control specimens from 

 persons of various ages that I had made. In these sections I found that 

 the dilatator was as a rule very conspicuous in the form of the Bruch's 

 membrane, even in ordinary, non-depigmented sections. Occasionally, it 

 is true, in a section of a normal iris it happened that the Bruch's membrane 

 was not visible, probably owing to local conditions, e. g. stretching or 

 folding during the process of imbedding, with consequent oblique sections; 

 but if several sections from the same iris be examined, there will never be 

 any difficulty in finding it. The difficulty with regard to the dilatator 

 question has not been the finding of the membrane of Bruch, but the 

 explanation of it; and this was only discovered when we became acquainted 

 with the methods of depigmentation. 



Even in the greater number of the non-depigmented sections the 

 absence or defective development of the membrane of Bruch in Miosis 

 congenita is clearly seen, but this abnormality is still more marked in the 

 depigmented sections. The characteristic feature of the sections is the 

 epithelium, ichich continues rigid up to the stroma. It is probably the 

 direct contact of epithelium with stroma that causes the epithelial cells to 

 come out better in these than in the control sections. The epithelium is 

 as a rule well preserved, except in the immediate vicinity of the pupil, 

 where it is absent. It consists of large, well-fixed cells. Occasionally only 

 a single cell has as it were swelled up and is badly stained, but this I am 

 inclined to ascribe to cadaveric changes, as the eyes were not fixed until 

 61 hours after death. These cadaveric changes are found especially in the 

 peripheral part of the iris. The nuclei as a rule come out sharply and 

 clearly, and the cell-borders are also generally very distinct. This is espe- 

 cially the case with the posterior cell-layer (see fig. 8), where there are 



