The Microscope. 49 



striium for the microscopist's use. A common mistake among 

 those who mount microscopic objects, especially at the begin- 

 nino- of their career, is to think that benzol and benzine are the 

 same thing under slightly different names. They are entirely 

 distinct, and benzine cannot be used in the place of benzol. 

 Benzine is made from petroleum, while benzol is a product of 

 the distillation of coal tar. In chemical composition they are 

 said to be somewhat similar, but in action on the objects and 

 on the mounting media that the microscopist uses they are as 

 unlike as possible. The microscopist never has need of benzine. 

 Gasoline, another petroleum product, can be advantageously 

 employed for the cleaning of old slides that have been discarded, 

 and the ©leaning of the brushes that have been used in the 

 cements and the mounting media. For these purposes gasoline 

 is very convenient and useful, but for this only. Benzine might 

 answer the same purpose, but I do not know that it has ever 

 been tried. Gasoline, I know from personal experience, is an 

 excellent cleaning agent. 



BEFERENCE TABLES FOR MICROSCOPICAL 



WORK.— Y. 



CARMINE AND HEMATOXYLIN STAINS. 

 COMPILED BY PROFESSOR A. B. AUBERT. 



ALUM CARMINE: carmine, 0.5 to 1 grm.; alum, 1 to 5 

 grms.; water, 100 grms. Boil 10 to 20 minutes and filter. 



Alum cochineal: 1, cochineal, 1 grm.; 2, burnt alum, 1 grm.; 

 3, water, 100 grms.; 4, carbolic acid a drop or so. — 1 and 2 to be 

 rubbed up in a mortar ; 3 is then added and boiled until about 

 50 c. c. remain ; add a drop or two of 4 and filter. Nucleus 

 stain. 



Alcoholic carmine: carmine, 0.6 grm.; ammonia, 2 grms.; 

 glycerine, 60 grms ; alcohol, 15 grms., water, 60 grms. Boil 

 carmine with ammonia until dissolved, add the mixture of gly- 

 cerine, alcohol and water ; filter. It is well to keep the solution 

 slightly alkaline by the occasional addition of a few drops of 

 ammonia. 



Borax carmine: 1, carmine, 0.5 to 0.75 grms.; 2, borax, 4 

 grms.; 3, water, 100 grms.; 4, acetic acid, sufficient quantity. 



4 



