1923. No. 23. A CASE OF CONGENITAL MIOSIS. 7 



a binocular microscope, exsected the lens and its capsule to an extent 

 that would enable me to form an opinion as to the condition of the posterior 

 surface. I was, of course, unable to avoid now and then injuring the iris, 

 and the light spots in fig. i are the marks of my instruments. It will be 

 seen from the figure, however, that the posterior surface of the eye is 

 much smoother than that in fig. 2, of a normal iris from a man of 65. 

 Both these drawings were made by the draughtswoman of the Anatomical 

 Institute, Fröken Mörch, and the preparations lay under the same binocular 

 microscope. 



With regard to the depigmentation of my material I may sa}' that it 

 has been carried out in every particular in the manner described in my 

 previous paper. The experience that I have gradually gained in depig- 

 menting the iris has taught me that it is unnecessary to embed it first in 

 thin celloidin. The way in which I now proceed is to place the exsected 

 iris, which was removed together with the ciliary body, in 80 per cent, 

 alcohol, and allow it to remain there for two or three da3^s in order to 

 give it a certain stift'ness. This is a great advantage, because the small 

 sectors do not curl up so easih' during the subsequent embedding. After 

 the iris has been in the alcohol, I return it to water and divide it either 

 into sectors, which are subjected to depigmentation, or I first depigment it 

 in toto and then cut it into sectors. This has been done, in this case 

 also, by Alfieri's method. As the work connected with this case was carried 

 out during the autumn months, when tliere is not an abundance of sunshine 

 in Christiania, it occurred to me that the sun's chemical rays might perhaps 

 be replaced by electric light, and I accordingly placed the material that had 

 been treated with potassium permanganate in a vessel containing an oxalic 

 acid solution beneath an ordinary electric bulb', and saw, to my great joy, 

 that the material bleached very rapidly. I found, indeed, that even a ' 2 

 per cent, solution of oxalic acid is sufficient to cause bleaching, whereas 

 b}' Alfieri's method a 2 per cent, solution is emplo3-ed. I think that the 

 fact oi' being able to do with so weak a solution is not without importance 

 to the result, nor can it be a matter of indifference that the bleaching could 

 be attained in a far shorter time than I have frequently had to take when 

 the sunshine was weak. 



I think the material should lie in the potassium permanganate solution 

 for a comparatively long time, so that there is a certainty of finishing the 

 bleaching in one operation, for I have seen the material fall to pieces when 

 the bleaching has not been completed the first time and I have attempted 

 to repeat the experiment by placing it once more in the potassium per- 

 m inganate solution. I therefore recommend a rather longer treatment at 

 first with the oxidising fluid. Sometimes I have not been quite successful in 

 depigmenting the material in this wav, but for what reason I cannot say. 



' Precaution must be taken that the water does not get hot. 



