848 SUMMARY OP CURRENT RESEARCHES RELATING TO 



Mayer's Modification of Grenadier's Carmine.* — Dr. P. Mayer thus 

 modifies Grenadier's carmine : — 4 gr. carmine are dissolved by boiling in 

 15 cc. water and 30 drops of bydrocbloric acid ; 95 cc. of 85 per cent, 

 alcohol are then added, and the mixture then neutralized with ammonia. 



Acid Chloral hydrate Carmine.f — ^Dr. Kultschizky recommends a car- 

 mine stain which is prepared by mixing chloral hydrate 10 grms., hydrochloric 

 acid, 2 per cent., 100 cc, and 1 grm. dry carmine. The mixture is boiled 

 from an hour to an hour and a half in a flask. Too much evaporation is 

 prevented by corking the flask, and passing a glass tube through the cork. 

 The solution is allowed to cool for twenty-four hours, and is then filtered. 



Thus prepared, the solution gives a red stain, but if a violet be preferred, 

 the sections are to be immersed in a 2 per cent, alum solution afterwards. 

 The omission of the acid gives a neutral solution, which may be used in 

 conjunction with Grenacher's alum-carmine and also picric acid, and a double 

 stain thereby obtained. 



ISew method!for making Picrocarmine.J — Dr. N. Lowenthal supersedes 

 ammonia with the hydroxide of sodium in preparing picrocarmine. Picro- 

 carminate of soda is a very powerful stain, especially for the central nervous 

 system. 



(1) The carmine solution is composed of water 100 cc. ; sodium hydroxide 

 1 g. ; carmine • 4 g. The sodium is dissolved in the water, and the carmine 

 added. The solution is effected in the cold in 24 hours, and in 10-15 

 minutes with the aid of heat. The solution is then filtered. 



(2) To solution No. 1, 100 cc. of water is added, and then 20-25 cc. 

 of a 1 per cent, solution of picric acid poured in. The solution, which is 

 rather cloudy, is allowed to stand for about an hour, and is then filtered 

 twice or thrice. 



Employment of Perruthenie Acid in Histological Ilesearches.§ — Prof. 

 L. Eanvier has a note on the employment in histological researches of per- 

 ruthenie acid, and its application to the study of the vacuoles of calyciform 

 cells. He has learnt, from a demonstration of M. Debray, that this acid 

 (EuO*) is reduced in the presence of organic bodies much more actively 

 than in osmic acid. This reducing action is so rapid and so easy that the 

 retrolingual membrane of the frog, although it contains a number of very 

 different elements, becomes completely black when subjected to the influence 

 of the vapour for a few minutes. If we gradually diminish the time of 

 action, it will be found that the membrane is darkened for a diminishing 

 thickness, but all the elements comprised in one layer are equally blackened. 

 If the time of exposure has been very short, the cilia of the epithelial cells 

 may alone be blackened. 



This " brutality " of perruthenie acid seems, at first sight, to deprive it 

 of all value as a histological reagent, but Prof. Eanvier reflected on Ihe mode 

 of action of osmic acid, and coming to the conclusion that the result of ex- 

 posure to osmic acid is a sort of metallization of the organic elements, he 

 judged that those which were the least blackened were the least metallized. 

 If this were so, the mucigen which remains uncoloured in the retrolingual 

 membrane treated with osmic acid would offer the largest amount of dis- 

 posable organic substance. After the retrolingual membrane has been 

 exposed to the vapour of osmic acid from ten to twelve hours the calyciform 

 cells appear as clear colourless circles. If now submitted to the action of 



• Internat. Monatschr. f. Anat. u. Physiol., iv. (1887) Heft 2. 



t Zeitschr. f. Wiss. Mikr., iv. (1887) pp. 46-8. 



X Anat. Anzeig., ii. (1887) pp. 22-4. § Comptes Kendus, cv. (1887) pp. 145-9. 



