ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 265 



as possible after the ewe's death. The slice is placed in saline (0*8 p.c.) 

 on a slide ; at a short distance therefrom is made a mixture of artificial 

 serum and of saturated aqueous solution of methyl-violet 5 B. The 

 mixture is then run on to the cartilage. As soon as the slice of cartilage 

 becomes violet, a cover-glass is imposed and ringed round with paraffin. 

 In this way a preparation is obtained wherein the mitochondria are 

 stained deep violet. When a cell is non-vacuolated the mitochondria are 

 massed around the nucleus ; if vacuolated they are scattered and isolated. 



New and Quick Method for Staining Spirochetes in Smear 

 Preparations.* — A. A. W. Ghoreyeb uses the following solutions : 

 (1) 1 p.c. osmic acid ; (2) Liq. plumbi subacetatis diluted one hundred 

 times with distilled water ; must be fresbly prepared ; (3) 10 p.c. 

 aqueous solution of sodium sulphide. The smear is stained as follows : 

 (1) cover with osmic acid solution for 30 seconds ; (2) wash in water ; 

 (3) cover with lead subacetate for 10 seconds ; (4) wash in water ; (5) 

 cover with sodium sulphide solution for 10 seconds ; (6) wash in water. 

 This process is gone through three times. Following this, the osmic 

 acid solution is applied for thirty seconds, and then the specimen is 

 washed in water, dried, and mounted in balsam. After the application 

 of each solution the washing with water must be thorough. The 

 illustrations are both £ood and instructive. 



& v 



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



New Mounting Medium for Botanical Preparations. f — S. Balint 

 has devised a medium for mounting botanical specimens which has a 

 refractivity equal to that of glycerin, or with glycerin-gelatin. It does 

 not crumple up sections of soft vegetable tissue, and finally becomes 

 so hard that ringing is unnecessary. It is composed of gum arabic 

 40 grm., loaf-sugar 60 grm., distilled water ad lib., glycerin 10 c.cm., 

 acetate of potash 10 grm., lacto-phenol 10 c.cm., glacial acetic acid 

 10 c.cm. The gum arabic must be finely powdered, and a solution made 

 which will filter easily ; the loaf-sugar must be melted to prevent its 

 tendency to crystallization ; a thin solution is then made which is mixed 

 with the filtered gum-solution, the acetate of potash is then added, and 

 the mixture is then thickened in a water-bath. When the required 

 inspissation is attained, the glycerin, lacto-phenol and glacial acetic acid 

 are added. After the ingredients are thoroughly mixed, the medium is 

 distributed into flasks, and these are immersed up to the neck in warm 

 water and kept warm in a water-bath for some hours and then allowed 

 to cool gradually. This procedure is necessary in order to get rid of air- 

 bubbles, and it should be repeated on the following day. Finally, to 

 every 200 c cm. of the medium 6 drops of lacto-phenol and 10 drops of 

 acetic acid must be added. The medium must be preserved in stoppered 

 bottles. One of the recommendations of this new mounting medium is 



* Publications Massachusetts Gen. Hosp., iii. (1910) pp. 367-9 (3 figs.), 

 t Zeitschr. wiss. Mikrosk., ixvii. (1910) pp. 245-7. 



