" PICRO-CARMINATE OF AMMONIA.'^ 251 



Note on " Picro-Carminate of Ammonia." By E. 



Cresswell Barer, M.B. Loud. 



(Read before the Medical Microscopical Society, March 20, 1874.) 



In this note I wish to draw attention to a microscopic 

 staining fluid which, as far as I am aware, is very little, if at 

 all, known or used in England. This fluid is the picro- 

 carminate of ammonia, invented by M. Ranvier, and largely 

 used in his laboratory at Paris. 



M. Ranvier first described this fluid in 1870, but since 

 that time he has made considerable changes in its method of 

 preparation. 



I propose to describe shortly the method of preparation 

 and employment, the way in which it colours tissues, and, 

 finally, to indicate some of its advantages over other staining 

 fluids in use. The picro-carminate of ammonia is made by 

 mixing — 



Carmine (best) 1 gramme. 



Liq. Ammonise .... 4 cubic centimet. 

 Water 200 grammes. 



Add to the mixture five grammes of picric acid, and after 

 agitating, decant, leaving the excess of picric acid. The 

 decanted liquor is then left for several days in a bottle, being 

 agitated from time to time. Then evaporate to dryness by 

 exposure to the air in a shallow vessel. This takes two, 

 three, or more weeks, according to the time of year. The red 

 powder which has thus formed is then scraped from the 

 bottom, and can be kept either in this form or as a liquid 

 ready for immediate use. The liquid is made by simply 

 dissolving the powder in water in the proportion of about 

 two parts of powder to 100 of water, allowing it to stand for 

 a few days and filtering. The filtering is best done through 

 a double layer of filtering paper, as otherwise solid particles 

 are apt to pass through. The liquid thus made ought to 

 have a yellowish red appearance and ought not to smell of 

 anmionia. To prevent the formation of fungi a few drops of 

 a solution of carbolic acid must be added. The liquid can 

 then be kept an indefinite time, requiring only occasional 

 filtration. 



The picro-carminate of ammonia not being a definite 

 chemical compound, is sometimes troublesome to prepare, 

 but the quantities mentioned in the above method appear to 

 give as good results as any.^ It is therefore always advisable 



• For the above quantities, as well as for several other hiuts on Picro- 

 Carmine, I am indebted to M. Malassez, Eepetiteur at the College de 

 France, Paris. 



VOL. XIV.— NEW SEE. R 



