SIS MICROSCOPICAL TECHNIQUE. 



ness which the dry dammar naturally possesses. The mounting 

 medium thus prepared is far too thin for immediate use, but this 

 is easily remedied by leaving the bottle open, or loosely corked, in 

 a warm place for a day or two. If left open, cover the top of the 

 vessel with a bit of lint cotton or a linen rag to keep out dust. 



Structure of the Bacteria."^— Sjobring has worked with the 

 Bacillus anthracis, a hay bacillus, a vibrio, and several forms of 

 cocci. He fixed the preparations by means of nitric acid, with or 

 without alcohol, and stained with carbol-methylen blue or carbol- 

 majenta red, afterwards decolouring with nitric acid and examin- 

 ing in glycerine and water. 



Formula for making Picro-Carmine Stain.t— (i) Carmine, 

 I grm. ; liquor ammoniae, 4 ccm. ; mix and add 5 grms. picric 

 acid. (2) Carmine, 15 grms.; picric acid, concentrated solution. 

 Agitate the mixture ( i ) from time to time for two days, let it settle, 

 decant, and evaporate decanted liquor at ordinary temperature, 

 re-dissolve the dry residue in w^ater, making i per cent, or 2 per 

 cent, solution ; filter when necessary. Triturate the carmine in 

 water until very fine, add enough ammonia to dissolve the carmine, 

 to this add slowly the concentrated solution of picric acid until the 

 mixture has a blood-red colour, keep in a shallow dish until all 

 odour of the ammonia has disappeared, filter, keep in a well- 

 stoppered bottle, add a few drops of carbolic acid ; filter before 

 using. 



Staining Small Organisms with picro-carmine and eosin-t— 



A solution for staining small organisms with these stains can be 

 made as follows : — Solution of a j per cent, of picro-carmine, 

 I part ; watery solution of a 2 per cent, of eosin, i part. The 

 organisms to be stained should be left in the solution for from 

 three to four days, and then washed^in 70 per cent., and then in 

 90 per cent, alcohol. 



Formula for Chloral Carmine. |l —Chloral carmine stain may be 

 prepared by heating together on a water bath, for thirty minutes, 



* Cent)-, f. Bakt. ii. Paras it, 

 \ Journ. Brit. Denial Assoc. ^ xiv. {1893), P- 248. 

 X Journ. Brit. Dental Assoc, xiv. (1893), p. 248. 

 WJonrn. Brit. Dental Assoc, \iv. (1893), pp. 248 — 249. 



