PART II. ANATOMICAL. 



BY 



O. BERNER. 



Tf 



he small pieces of the iris removed by iridectomy were sent to me 

 by Dr. Holth for examination immediately after the operation, but notwith- 

 standing great care in stretching them out on paraffined cork plates, etc., 

 they curled up so much that it was impossible to make anything of the 

 material. My investigations are therefore based entire!}' upon the study of 

 the irises of the two e3'es that were not fixed until about 6i hours after 

 death. These, when I received them, were lying in Bouin's fixing liquid, 

 of which Dr. Holth had, moreover, before the post-mortem enucleation, 

 injected sufficient into the vitreous body to prevent the cadaveric collapse 

 of the bulb. 



As I knew from former work with the iris how frequently paraffin 

 sections came off the slides after depigmentation, and as, with this unusual 

 material, it was important not to lose a single section, I decided to imbed 

 the material in celloidin, and the first sections I examined were therefore 

 ordinary celloidin sections with a thickness of about 12 //. They were 

 stained in the usual way in van Gieson's liquid or with Böhmer's hæma- 

 toxylin and eosin; but as these dyes do not always give clear and distinct 

 results in sections that are depigmented by Alfieri's method — the method 

 I have always emplo3'ed — I subsequent!}- took to staining the sections, 

 like Forsmark, with iron-alum-hæmatoxylin according to Heidenhain's method, 

 and also counter-stained them with eosin. Like Forsmark, I strongly 

 recommend this staining, for when properly done with suitable differentia- 

 tion it is fully equal to van Gieson's method, perhaps, indeed, even superior 

 in clearness, and further has the great advantage of making the sections 

 thus stained preservable for any length of time. 



As depigmentation of sections is a method in which much time is 

 wasted, and as, for purposes of control, I have had to examine many 



