3O MICRO-CHEMICAL REAGENTS. 



Resins are soluble in ether, cold absolute alco- 

 hol, carbon bisulphide, and oil of turpentine. 



Fatty oils are soluble in carbon bisulphide, ethe- 

 real oils, hot alcohol, and ether. When treated 

 with concentrated potassic hydrate they form 

 soaps, which are soluble in water. 



Ethereal oils are easily soluble in oil of turpen- 

 tine and cold absolute alcohol. Most of them are 

 also dissolved by ether and carbon bisulphide. 1 



It will be seen that their behavior, when treated 

 with alcohol, is distinctive for fatty and volatile 

 oils ; but for resins other reactions must be relied 

 upon, which will be spoken of later. 



The substances which dissolve fatty oils may also 

 be used as reagents for wax. 



With respect to the application of these reagents, 

 we can only say that since carbon bisulphide, ether, 

 oil of turpentine, and benzol are insoluble in water, 

 the sections should be placed immediately in them 

 to secure the best results. They cannot be pre- 

 pared in water which is replaced by allowing the 

 reagent to penetrate under the cover-glass, as with 

 so many other reagents. The most convenient 

 plan is to treat the sections in a watch-glass, with 

 a considerable quantity of the reagent. 



1 Dippel (Mikr., I., p. 374) states that they are insoluble in ether, 

 which I do not understand. 



