ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 117 



emulsion, dried this quickly in air, added a droplet of water, and applied 

 a coverslip carefully. This was then ringed with paraffin to prevent 

 evaporation. 



The author obtained good results by using a solution containing 

 :> grm. of iodine and 3 grm. of potassium iodide in 20 c.cm. of water. A 

 small drop of the fine emulsion of spirilla was placed on a clean slide, 

 and to this a larger drop of iodine solution was added. A coverslip 

 was then placed in position, and ringed with paraffin. 



For demonstrating minute cellular structure and the intracellular 

 connections of flagella, the organisms were fixed in corrosive sublimate, 

 or in weak Flemming's solution. The bacterial emulsion was placed in 

 a filter-paper folded in the usual way in a filter funnel. The fixing 

 fluid caused the organisms to cohere in clumps, so that none passed 

 through the filter.-paper. Alcohols of mounting strengths were added, 

 and then xylol and xylol-paraffin. Finally, the organisms were imbedded 

 in paraffin, fine sections (2-4 /a) were cut and stained with methylen- 

 blue or methylen -green. 



New Staining- Reaction for Tubercle Bacilli.* — D. Gassi stains 

 the fixed smears in a warm solution of eosin for one or two minutes. 

 The solution consists of 1 p.c. eosin solution, to 5 c.cm. of which a 

 crystal of sublimate the size of a lentil has been added. After washing 

 in water the smear is treated with a mixture of • 5 NaHO, 1 potassium 

 iodide, 100 of 50 p.c. alcohol, until it assumes a pale green hue, after 

 which it is further treated with alcohol and afterwards washed in water. 

 The preparation is next contrast-stained with acid methylen-blue for 

 2 or 3 seconds (methylen-blue 1, absolute alcohol 10, | c.cm. hydro- 

 chloric acid and 90 c.cm. distilled water). After a thorough wash it is 

 dried and mounted. The tubercle bacilli are red, the rest blue. By 

 this method tubercle can be distinguished from smegma bacilli, as the 

 latter are not alkali-fast. 



Demonstrating the Presence of Lipoids in Cells, f — C. Ciaccio 

 recommends the following procedure : — 1. Pieces a few millimetres 

 thick are fixed in Ciaccio's fluid for 21 to 48 hours (5 p.c. bichromate 

 of potash, 100 c.cm. ; formalin, 20 c.cm. ; formic acid, 4 or 5 drops, or 

 acetic acid, 5 c.cm.). 2. Immersion of the pieces in 3 p.c. bichromate 

 for a week. 3. Washing in running water for 24 hours. 4. Upgraded 

 alcohols for 24 hours ; absolute alcohol, 2 hours ; absolute alcohol and 

 sulphide of carbon (or xylol or chloroform), 1 hour ; sulphide of carbon, 

 1 hour ; paraffin, m.p. 60°, dissolved in sulphide of carbon at 37°, 

 1 hour ; paraffin, m.p. 55-G0°, 1 hour. The sections are stuck on 

 the slide by Henneguy's method (very dilute solution of gelatin in 

 tepid distilled water, with a crystal of potassium bichromate added). 

 The sections are then stained with an alcoholic solution of Sudan iii. for 

 30 to 45 minutes, or with scarlet R. Excess of stain is then removed 

 with 50 to GO p.c. alcohol. The sections may then be contrast-stained 

 with hamiatoxylin, water-blue, crystal-violet, etc., and are imbedded 

 in Apathy's gum and syrup medium. In some cases the following 



* Centralbl. Bakt., ]> Abt. Ref., lxiv. (1909) p. 758. 

 t Anat. Anzeig., xxxv. (1909) pp. 17-31. 



