1923- No. 23. A CASK OF CONGENITAL MIOSIS. [3 



"hook"; but in the middle of it have been left some cells which have 

 retained the properties of the epithelial cell, and moreover have not diffe- 

 rentiated myoglia fibrils. 



The musculature which may be developed in connection with a "hook" 

 such as this, can be very large. Fig. i6 shows a section a little to one 

 side of the "hook" itself, but it will be seen that a thick disc of muscle 

 has constricted oft' a little island of stroma, and that this island is left lying 

 behind the plate of muscle (which is connected above with the dilatator 

 muscle) and in front of the epithelium of the iris. As the latter, here too, 

 has developed some contractile substance, the separated lump of stroma is 

 left in the middle of a space which is bounded in front and behind by the 

 dilatator muscle. 



These sharp "hooks", as I have said, almost always make their way 

 at once out towards the ciliary processes; but occasionally it is seen that 

 the epithelium of the iris pushes itself in in the form of a protuberance 

 which turns inwards towards the pupil. These, too, turn oft' again, however, 

 in an outward direction, although the course is long and devious. In the 

 letter-press fig. i', some sections are given of a very long protuberance 

 of this kind. In section a is seen the place where the iridian epithelium 

 turns forward into the stroma. Between this section and the next shown 

 in the illustration, /;, there are six sections. In this section there is still 

 connection with the epithelium of the iris; but in the next section, c, which 

 is four sections farther on in the series, there are sone small lumps of 

 pigment surrounded by contractile substance (dilatator muscle), lying isolated 

 in the stroma in front of the iris pigment, and they retain this position through 

 sections d, c,f, and g, the only dift'erence being that they gradually move farther 

 and farther down towards the ciliary body, and in section g have come 

 right in under a ciliary process. It is evident, from the unaltered appearance 

 of the posterior surface of the iris through all these sections, that this is 

 a growth of epithelium into the stroma, and not a fold-formation. 



I have also gone through my various series with regard to some other 

 of these formations. Concerning fig. i6 it may be said that this sharp "hook" 

 was soon dissolved into small patches of iridian epithelium, each fragment 

 being surrounded bv smooth muscle-substance, and that after 12 sections 

 a "hook" once more developed, which was identical with the one photo- 

 graphed. In the interval between these two "hooks" the fragments lying in 

 the stroma had drawn together and become one with the posterior iridian 

 epithelium; and there can therefore be no doubt that what is shown by the illu- 

 strations can only be explained by a growth of the epithelium into the stroma. 

 I have found many such "epithelial processes" and "hooks" in my 

 various series, and have followed them from beginning to end without 



1 There are 3 figures in ths text. All the other references to illustrations concern the 

 Plates I — IX, fig. I — 19. 



