ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 113 



alcohol is made and the preparations treated therewith for \ to ^ hour. 

 Even the smallest drops of fat are stained a bright red. The prepara- 

 tions may be contrast-stained with Bohmer's hematoxylin, and should 

 be mounted in glycerin or in la3vulose syrup. 



Staining Woody Tissue. * — L. Mangin has examined the selective 

 staining action of naphthylamin, toluidiu, benzidin, tolidin and dianisi- 

 din. The first two stain the ligneous tissue yellow, while benzidin and 

 dianisidin impart a red-brown hue. Tolidin gives a dull brown. He 

 prefers benzidin, of which a solution is prepared by dissolving 1 grm. 

 together with 1 grm. of acid (citric, tartaric, or lactic) in 100 ccm. of 

 water. After boiling the mixture is filtered. The simple solution may 

 be used, or some glycerin added to the filtrate. 



Demonstration of the Cell-nucleus of Saccharomyces. f — C. Hoff- 

 meister recommends the following solutions for fixing, viz. von Path's 

 and Merkel's solutions, percbloride and iodo-potassic iodide. 



The best staining results were obtained with Bohmer's haematoxylin 

 and with Heidenhain's iron-hsematoxylin. The procedure adopted was 

 the following : — The yeast-cells were fixed with von Bath's mixture, 

 and after washing out the fixative, films were made on cover-slips from 

 suspensions. When dry the slips were floated on 2*5 p.c. iron-alum 

 solution for 6-24 hours. They were then washed again, and transferred 

 to 0*5 p.c. aqueous hematoxylin solution for at least 24 hours, after 

 which they were differentiated in J p.c. iron-alum solution. The cyto- 

 plasm is decolorised, the nucleus remaining black, violet, or dark grey. 



Modifications of Weigert's Method of Staining Elastic Tissue.^ — 

 Dr. B. Minervini has obtained satisfactory results from the following 

 procedures : — (1) Staining in bulk : the pieces are fixed in formalin 

 alcohol or Mulder's fluid. Pieces about 1 ccm. are immersed in the stain- 

 ing fluid for 48 hours, after which they are transferred to alcohol with 

 1 per cent. HC1 for 24 hours ; next, to 90 per cent, alcohol for a 

 similar period, and finally to absolute alcohol, turpentine, or xylol, and 

 imbedded in paraffin. The pigment is made by precipitating an aqueous 

 solution of fuchsin with iron chloride and dissolving the precipitate in 

 alcohol. 



(2) An aqueous 1 p.c. solution of safranin with 1 p.c. resorcin is 

 made. When cool it is filtered. To the filtrate a quarter of its bulk of 

 iron chloride is added. The solution is heated to boiling, and the 

 residue after filtering is washed, dried, and dissolved in 100 parts of 

 90 p.c. alcohol with 1 p.c. HC1. The sections are stained for two hours, 

 decolorised in alcohol, and may be contrast-stained with hematoxylin 

 or methylen-blue. This pigment is quite suitable for stainiug tissue in 

 bulk, especially if fixed with some chromic acid 6alt solution. Indeed, 

 Weigert's method or its modification is always improved by the presence 

 of chromic acid or one of its salts. 



(3) An aqueous 1 p.c. solution Jwith 1 p.c. resorcin is prepared by 

 the aid of heat. When cold it is filtered, and a quarter of its volume of 



* C.R. Soc. de Biol., liii. (1901) pp. 837-9. 



t SB. Deutschen naturwiss.-med. Yereins f. Bohmen "Lotos," xx. (1900) 

 pp. 251-63 (1 pi.). See Bot. Centralbl., lxxxvii. (1901) pp. 129-30. 

 J Zeitechr. f. wiss. Mikr., xviii. (1901) pp. 161-5 (1 pi.). 



Feb. 19th, 1902 I 



