ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 241 



tissue. These two solutions are used alternately, commencing with the 

 acid, the section being frequently observed under a low power until 

 the desired colour contrasts are obtained ; the cell nucleus being seen 

 of a deep Romanowsky red colour, and the rest of the tissue pale pink 

 or a light blue ; the section is washed in water and rapidly dehydrated, 

 and then mounted in balsam. 



Glycogen Staining.* — L. F. Driessen stains the glycogen in 

 animal tissues by the following method. Celloidin or paraffin sections 

 are transferred from alcohol to an alcoholic cochineal solution or to 

 Mayer's carmin solution. They are next treated with !)5 p.c. alcohol 

 and absolute alcohol (3 minutes) after which they are placed in iodin- 

 carbol-xylol solution for 3-5 minutes. If overstained, they are washed 

 in carbol-xylol. The preparations are mounted in balsam. 



The iodin-carbol-xylol mixture is prepared by placing equal parts 

 of Lugol's solution and carbol-xylol in a test tube and shaking vigorously. 

 Some few drops of the supernatant iodo-xylol are pipetted off and placed 

 on the section, by which it is cleared up and the glycogen stained . The 

 section is then mopped up with blotting paper, and mounted in balsam. 



Section Staining by Romanowsky's Method.! — K. Sternberg fixes 

 the material in alcohol and stains the paraffin sections with Gieinsa's 

 modification of the Romanowsky method. Immediately before use, the 

 0*4-0 "5 c.cm. of the solution is diluted with 20 c.cm. of boiled distilled 

 water. After a lapse of 20-24 hours the sections are washed in water 

 and differentiated with 0*5 p.c. acetic acid. They are again washed 

 and then treated with alcohol, and finally passed through xylol and 

 mounted in balsam. 



Staining and Mounting Ossifying Cartilage. $ — M. Heidenhain, 

 when demonstrating the ossification of cartilage, fixes, and at the same time 

 decalcifies, small pieces in 5 p.c. trichlor-acetic acid, and after-hardens in 

 absolute alcohol, which must be repeatedly changed. The pieces are 

 imbedded in celloidin, and sections 20-25 /x thick are cut. 



The sections are stained with Delafield's hematoxylin, and afterwards 

 with borax-carmin. The preparations are best mounted in glycerin 

 jelly made as follows : — Gelatin 45, water 210, glycerin 35, absolute 

 alcohol 70 parts. The gelatin is first dissolved in the water, the glycerin 

 is then added, and the mixture filtered out at a temperature of 56°. To 

 the clear filtrate the absolute alcohol is added drop by drop, the solution 

 being vigorously stirred the while. Air-bubbles may be avoided by 

 fishing the sections out of the warm and liquefied medium, and placing 

 one on a cover-glass and pressing this firmly down on the slide. 



Staining the Chromophilous Cells of the Hypophysis cerebri.§ — 

 G. Cagnetto gives the following procedure. Fix one half of the hypo- 

 physis in 10 p.c. formalin for 3-4 days. Transfer to chromic acid 



* Centralbl. allgem. Pathol, u. pathol. Anat., xvi. (1905) pp. 129-31. 



f Tom. cit., pp. 293^1. 



j Zeitschr. wiss. Mikrosk., xxii. (1905) pp. 325-30. 



§ Tom. cit., pp. 539-43. 



April 18th, 1906 r 



