1883.] 



MICROSCOPICAL JOURNAL. 



IC9 



dried for mounting at some future 

 time. 



In our next article we propose to 

 describe the method of making trans- 

 parencies for the lantern for the illus- 

 tration of lectures. 



To be c on ti lilted. 



Histological Work. 



By J. F. Hazelwood. 



During the past two years I have 

 given especial attention to histology. 

 In my work I have followed mi- 

 nutely many of the methods sug- 

 gested by Beale, and with excellent 

 results. For the carmine stain, 

 however, I have used the preparation 

 given by Dr. Seller. Not satislied 

 with the differentiation of the single 

 stain, after many experiments I 

 secured a blue stain composed of 

 rosaniline, aniline oil, and sulphuric 

 acid. In this way, I get the finest 

 demonstration of tissues I have ever 

 seen ; for while the carmine gives the 

 nuclei, the blue will give the outlines 

 ()f the cells, fibrillce of muscles and 

 nerves, connective tissue, fibres, etc. 

 For instance, I had several tongues 

 of frogs, which had been stained with 

 carmine and mounted in glycerine 

 and acetic acid, after Beale, and left 

 for nearly two years sealed up in 

 glycerine. I took them out of their 

 cells and put them through the blue 

 stain, and then mounted each tongue 

 in a series of slides, with glycerine as 

 the medium, and got a magnificent 

 demonstration of simple and com- 

 pound papillse, with the branched 

 muscle-fibres and delicate nerves in 

 situ, also nerve-trunks and ganglion- 

 cells ; such a demonstration, indeed, 

 as delights the heart of the histologist. 



The skin of the frog has by the 

 use of this same double stain, fur- 

 nished another means of studying the 

 beautiful arrangement of the nerves. 

 Even the most delicate nerve-fibres 

 are thus brought out with great dis- 

 tinctness, so that one can readily find 

 them with a low power, and at once 



turn upon them his highest objectives. 

 In vertical sections of nerve-trunks, 

 by this treatment, the outline of the 

 individual sheaths is distinctly given, 

 with the axis-cylinder in the centre 

 — a most beautiful sight. So great 

 is the change wrought by this blue 

 stain, that I have dismounted many 

 of my old slides, and put them 

 through this process, and then re- 

 mounted in balsam or glycerine at 

 pleasure. 



This stain gives equally surprising 

 results in differentiating the tissues 

 of insects. Nerves and tracheae and 

 cell-walls are finely colored. The 

 most beautiful liver-cells I ever saw, 

 were thus double-stained. The fine 

 net-work of muscles and nerves on 

 the stomach and intestines and on 

 the glands, is thus brought out with 

 stereoscopic effect. I have, in this 

 way, on the beautiful muscles of the 

 lampyridae, distinctly seen the acces- 

 sory discs of Engelmann. 



One of the most gratifying results 

 thus obtained, was the demonstra- 

 tion of the nerves and ganglia in 

 the thin membrane of the bat's wing. 

 I had long admired Beale's famous 

 slides of this tissue ; but it will be 

 remembered that he tore off the 

 upper and lower skin, after long 

 soaking in glycerine, and saved the 

 the middle tissue. Wishing, how- 

 ever, to save as much as possible, I 

 scraped off the hair and pigment 

 cells while the wing was in a solution 

 of liquor potassce. In this way, I saved 

 many fine nerve-fibres and beautiful 

 ganglion-cells, which do not appear in 

 Beale's diagrams. These cells and 

 nerves are brought out spiendidly by 

 the blue stain. 



In a constant study of tissues for 

 the past year, by means of this 

 double stain, I have been continually 

 reminded of the remarkably accurate 

 work of Beale, especially as respects 

 the demonstration of nerves. 



For objectives in my own work, I 

 have used a Tolles -^-^ homogeneous, 

 — a magnificent lens! — and a Tolles 

 \. The latter was made especially 



