ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 787 



Dahlia is made up with 90 p.c. alcohol in 10 p.c. solution. One drop 

 of a 10 p.c. solution of this fluid in water is mixed with the suspension 

 of casts or bacilli, and covered with a cover-slip. The slide is then 

 examined directly without removing the excess of stain. For examining 

 fixed smears a 5-6 p.c. watery solution of dahlia is used. 



Stable Solution of Gentian-violet.*— Kilduffe recommends the 

 following as a stable solution of this stain for use in Gram's process : — 

 Saturated gentian -violet solution, 25 p.c. ; 5 p.c. formalin, 75 p.c. 



Staining Prowazek's Bodies. | — K. Lindner describes a method of 

 staining by means of which these cell-inclusions — the causal agents of 

 trachoma — may be demonstrated and readily distinguished from artefacts. 

 A film is made upon a cover-slip, dried in air, and fixed in absolute 

 alcohol. It is then left for 1 hour in a solution containing five drops 

 of Giemsa and one drop of 1 p.c. acetic acid in 10 c.cm. of distilled 

 water. Then it is dried and mounted. On a film so stained, these 

 bodies appear dark blue or pale blue, the early stages being strongly 

 basophil, the later stages less markedly so. The films show contrast- 

 staining of such a type that it is a relatively easy matter to pick out these 

 bodies during rapid examinations of microscopic fields. 



(5 Mounting-, including- Slides, Preservative Fluids, etc. 



Mounting Serial Celloidin Sections.:}: — N. Anitschow makes use of 

 the following method. The sections as they are cut are placed in 65 p.c. 

 alcohol and transferred by means of a spatula to albuminized slides. By 

 means of a small forceps, they are carefully spread upon the slide. This 

 process may be facilitated by the use of 98 p.c. alcohol, which softens 

 the celloidin. When quite flat, the sections are pressed firmly down with 

 filter paper. Then a mixture of anilin and clove-oil, or of alcohol and 

 formalin, is poured over the slide, and pressure is again applied. The 

 sections are then washed thoroughly with acetone, to remove all traces of 

 celloidin. The acetone is washed off with water, but, in the case of 

 delicate tissues an intermediate treatment with 70 p.c. alcohol is advisable. 



Mounting Frozen Sections.§ — N. Anitschow describes his method 

 as follows. By means of a spatula the sections are removed from the 

 microtome to a dish containing 50 p.c. alcohol, and from this to albu- 

 minised slides. The sections are spread out carefully, and pressed down 

 carefully with filter paper. The slide is then placed in 98 p.c. alcohol 

 for half a minute, transferred to 70 p.c. alcohol, and finally to water. If, 

 however, it is proposed to stain the sections for fat, the slide is placed 

 instead in 50 p.c. alcohol-formalin, and then transferred direct to water. 



(6) Miscellaneous. 



Gelatin Plates for Graphic Reconstruction.! — A. Pensa gives a 

 brief account of his method of using sheets of compressed gelatin for 



* Centralbl. Bakt., lte Abt. Kef., xlvii. (1910) pp. 407-8. 



t Op. cit., lte Abt. Orig., xlvii. (1910) pp. 429-32. 



% Zeitscbr. wiss. Mikrosk., xxvii. (1910) pp. 67-70. 



§ Tom. cit., pp. 71-4. || Tom. cit., pp. 48-50. 



