710 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
and glycerin hematoxylin. Stained specimens washed in alcohol con- 
taining a little eosin ; clear in oil of cloves ; mount in balsam. 
Picrocarmine. — I. Carmine, 1 grm. ; liquor ammonie, 4 ccm. ; mix 
and add 5 grm. picric acid. II. Carmine, 15 grm. ; picric acid, con- 
centrated solution. Agitate the mixture (I.) from time to time for 2 
days ; let it settle ; decant and evaporate decanted liquid at ordinary 
temperature ; redissolve the dry residue in water, making 1 per cent, 
or 2 per cent, solution ; filter when necessary. 
II. Triturate the carmine in a mortar until very fine ; add enough 
ammonia to dissolve the carmine ; to this add slowly concentrated 
solution of picric acid until the mixture has a blood-red colour ; keep in 
a shallow dish until all odour of ammonia has disappeared ; filter ; keep 
in a well-stoppered bottle; add a few drops of carbolic acid; filter 
before using. 
Picrocarmine and Eosin. — Solution of picric carmine, 1 per cent., 
1 part ; watery solution of eosin, 2 per cent., 1 part. For small 
organisms, 1/2 to 4 days ; wash in 70 per cent., then in 90 per cent, 
alcohol. 
Metallic Stains : — 
Ammoniacal Nitrate of Silver. — Silver nitrate, 0*75 to 0*5 per cent, 
with ammonia. Add to nitrate of silver solution enough ammonia to 
redissolve the precipitate which forms at first; dilute to 0*75 per cent, 
or 0*5 per cent. 
Gold Chloride. — A. Gold chloride, 1 grm. ; water, 2000 ccm. ; hydro- 
chloric acid, 30 drops. B. Alcohol, 1 part ; formic acid, 1 part. 
Sections treated with A, then transferred to B, where reduction of the 
gold takes place. 
Potassium Gold Chlonde. — A. Potassium gold chloride, 1 part; water, 
10,000 parts; hydrochloric acid, a trace. B. Water, 2 to 3000 parts; 
hydrochloric acid, 1 part. C. Alcohol, 60 per cent., 1000 parts ; hydro- 
chloric acid, 1 part. Sections hardened in ammonium bichromate are 
put in A for from 10 to 12 hours, until they are of a light violet colour, 
washed in B, and transferred to C. 
Osmic Acid and Silver Nitrate. — A. Potassium bichromate, 2 per 
cent., 10 parts; osmic acid, 1 per cent., 1 part. B. Silver nitrate, 
1 part ; water, 200 parts. Objects soaked in A for several hours, 
transferred to B for at least 8 hours. 
Silver Nitrate. — A. Silver nitrate, 0 25 to 0*5 parts; water, 100 
parts. B. Salt, 0*75 parts; water, 100 parts. Sections 20 to 40 
seconds in A, then in B ; move them about in both, then expose to the 
light. 
Silver Nitrate and Silver Iodide. — A. Silver nitrate, 1 part ; water, 
100 parts. B. Silver iodide, 1 part ; water, 100 parts ; potassium 
iodide, a trace. C. Silver nitrate, 0 ■ 1 part ; water, 100 parts. Put 
the sections in A (in the dark) ; after 2 or 3 minutes add a few drops of 
B ; wash the sections in water and expose for 2 days in C to the action 
of the light (cornea.) 
