ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 593 



point and allowed to cool. As the fluid cools the sections stain, and 

 are at their best in 3 to 4 minutes. (2) To 1 volume of Hover's picro- 

 carmin 19 volumes of distilled water are added. The sections are 

 treated as above, but the staining takes 10 to 15 minutes. 



Fixing, Staining and Mounting Sections of Skin.* — E. Retterer, 



in his researches on the structure of the skin, fixed the material in 

 Flemruing's, Zenker's or Branca's fluid, giving the preference to the two 

 last. The sections were stained by various methods : some with hgema- 

 toxylin, and fuchsin and Israel's eosin-orange-aurantia ; others with 

 fuchsin-resorcin, followed by hematoxylin and safranin (21 hours) ; 

 others with fuchsin-resorcin and alum-carmin ; others with lithium- 

 carmin, vesuvin and fuchsin-resorcin. The specimens were mounted 

 in glycerin, Farrant's medium, and balsam. 



The author pertinently remarks that if all the structure and details 

 of a histological specimen are to be made out satisfactorily no single 

 method will suffice, and that no rule can be given for determining a 

 priori the precise routine for obtaining the best results. 



New Method of Staining the Epithelial Fibres and the Mem- 

 brane of Prickle Cells.f — P. G. Unna fixes the material partly in 

 absolute alcohol, partly in formalin, hardens in alcohol and imbeds in 

 celloidin. The sections are stained in the following mixture : Water 

 blue 1 ; orcein 1 ; acetic acid 5 ; glycerin 20 ; spirit 50 ; water to 100. 

 One gramme of this solution is placed in a test-tube and mixed with 

 ' 3 grm. of 1 p.c. alcoholic solution of eosin, and then with ■ 3 grin, 

 of 1 p.c. aqueous solution of hydrochinon. The sections are stained 

 in the cold for 10 minutes. After washing with distilled water they 

 are immersed in 1 p.c. aqueous solution of safranin for 10 minutes. 

 They are again washed with distilled water, and transferred to J p.c. 

 bichromate of potassium solution for 10 to 20 minutes. On removal 

 the sections are washed in distilled water, after which they are de- 

 hydrated in absolute alcohol and then mounted in balsam. 



Should the sections (which should have a violet hue after dehydration) 

 be too red from excess of safranin, they must be re-treated with alcohol. 



Staining with Chrom-hsematoxylin.J — O. Schultze recommends 

 the following procedure for staining tissues previous to sectioning : 



(1) Fix the material in solutions of bichromate of potash or of chromic 

 acid, or better still, with osmic ackl added to both, for 12 hours or longer ; 



(2) 50 p.c. alcohol, in the dark for 24 hours or longer ; (3) 70 p.c. 

 alcohol with 0'5 p.c. hematoxylin, for 24 hours or longer ; (4) 80 p.c. 

 alcohol ; (5) absolute alcohol ; (G) imbedding : the sections should be 

 thin, not thicker than 5 jx. 



Modification of van Ermengem's Method of Staining Flagella.§ 

 J. "W. W. Stephens describes the following modification of van Ermen- 

 gem's method : (1) The mordant consists of 2 p.c. osmic acid, 1 part ; 

 tannin 20 p.c, 2 parts ; this is allowed to act for | to 1 hour or longer. 



* Journ. Anat. et Physiol., xl. (1904) pp. 337-86 (2 pis.). 



t Monatsch. prakt. Dermatol., xxxvii. (1903) pp. 1-18 (1 pi.). See Zeitschr wiss. 

 Mikr., xxi. (1904) pp. 68-9. 



\ Zeitschr. wiss. Mikr.. xxi. (1904) pp. 5-9. § Lancet, 1904, II. p. 22. 



