129 



126. Methylene blue. Formula : Methylene blue, satu- 

 rated alcoholic solution, i part ; distilled water, 2 parts. 



This is for staining " basophile " granules in mast cells. Prep- 

 arations fixed by heat or ether-alcohol are stained 15 minutes or so, 

 washed with water, dried, and mounted in balsam. Nuclei and bas- 

 ophiie granules stain blue ; all else is colorless, or nearly so. This 

 stain has but little value in the study of normal blood, since baso- 

 phile leucocytes are of rare occurrence. 



FINE INJECTION. 



For the purpose of examining microscopically the finer arteries 

 and veins and the capillaries in a tissue, and their relation to the 

 other parts, it is necessary to fill them with some colored injection 

 mass, or otherwise stain or color them. The masses employed for 

 the fine injection of tissue in this course are Carmine Gelatin Mass 

 (red) and Berlin Blue Gelatin Mass. 



127. Carmine gelatin mass. Formula : Dry gelatin, 75 

 grams ; carmine (No. 40), 10 grams water, 90 c.c. ; ammonia, 10 

 c.c. ; acetic acid, q. s. ; chloral hydrate, 10 grams. 



Soak the gelatin in water until it is soft ; pour off the superflu- 

 ous water and melt it (in an agate or porcelain dish) over a water 

 bath. Grind the carmine to a paste with water ; add all the am- 

 monia and water ; filter, warm to 80 or 90 C. , and add to the warm 

 gelatin. Then add slowly the acetic acid diluted with an equal vol- 

 ume of water, while constantly stirring the mass, until the mass 

 smells very slightly of the acid. Filter through fine flannel. If the 

 mass is acid, the chloral hydrate may be safely added (as a preserva- 

 tive) ; if any ammonia is present it will decompose it forming chlo- 

 roform and a granular precipitate. If too much acid is added, the 

 gelatin will not set. 



128. Berlin blue injection mass. Formula: Dry gela- 

 tin, 75 grams ; saturated aqueous solution of Berlin blue, 150 c.c. 

 chloral hydrate, 10 grams. Prepare the gelatin in the manner given 

 above ( 127) ; warm the Berlin blue solution (to 80 or 90 C.), 

 and add it to the hot gelatin. Heat the mixture for 10 minutes or 

 more, stirring it occasionally, and filter it through fine flannel and 

 add the chloral hydrate. 



