76 
Transactions of the Boyal Society of Soutli Africa. 
(1) Stain : Ziehl-Nielson solution of carbolic-fuchsin. 
Distilled water 
Carbolic acid .. 
Alcohol (abs.).. 
Fuchsin 
100 cc. 
5 gm. 
10 cc. 
1 gm. 
Or it may be prepared by adding a 5 per cent, aqueous solution of 
carbolic acid to the saturated alcoholic solution of fuchsin until a metallic 
lustre appears on the surface of the fluid. 
Method : After treating with KOH and washing, transfer direct to the 
stain. Leave for one hour if used cold. If heated until it steams, and 
then allowed to stand, the specimens will be well stained in ten minutes. 
Transfer direct to 70 per cent, alcohol. If over-stained wash quickly in 
70 per cent, alcohol containing a trace of hydrochloric acid. Pass through 
90 per cent, and absolute alcohol to oil of cloves and mount when cleared. 
(2) Stain : (Method of Professor E. Newstead and Dr. P. Marchal). 
Saturated solution of magenta in absolute (or 95 per cent.) alcohol. 
Method : After treating with KOH and washing, pass through the 
alcohols to 90 per cent , and thence into the stain. Leave to stain for 
20 to 30 minutes — or longer, wash in absolute (or 95 per cent.) alcohol, 
transfer to oil of cloves and mount in Canada balsam. 
The following equivalents and approximations may be useful for 
reference : — 
To make a dilution from a solution of known strength : Take the 
amount in cc. (or a multiple of that number) represented by the desired 
strength, and add water to the amount represented by the original per- 
centage in cc. (or the same multiple of that number). Thus, to make 
35 per cent, alcohol from 75 per cent., take 35 cc. of the 75 per cent, and 
make up to 75 cc. with water. 
In using formalin it must be borne in mind that this liquid contains 
only approximately 40 per cent, of formaldehyde when sold, so that to 
make a 4 per cent, solution take 4 cc. of ordinary formalin and make 
up to 40 cc. with water. 
1 = 1/1000 mm. 
1 mm. = 0-0393 inch. Approximately 25 mm. = 1 inch. 
1 gram = approximately 15|- grains (15-432). 
1 oz. = approximately 28 grams (28-349). 
1 fluid oz. = approximately 30 cc. 
1 litre = 1,000 cc. = 1*759 imperial pints; thus 4 litres = approximately 
7 pints. 
