»S0 APPENDIX. 



up to 95 p.c. or, absolute and then cleared previously 

 to being mounted in Canada balsam. 



Injection mass. 



a. Make a 2 p.c. aqueous solution of Berlin blue (this 

 may be bought at a chemist's); it may be injected 

 either cold or warm. The tissues after injection 

 should be placed in alcohol. The sections should be 

 cleared, and mounted in Canada balsam ; if the blue 

 has become a lighter colour during the stay of the 

 tissue in alcohol, the sections should be placed for 

 a day in turpentine in an uncovered watch-glass 

 or bell-jar. Injections made with this solution are 

 rarely so good as those made with the following 

 (6) (c). 



h. Place 20 grms. of gelatine in cold water until it is 

 well swollen, then pour off the water, and place the 

 gelatine in a water-bath at about 40° 0. (covering it 

 up to prevent evaporation) until it forms a fluid 

 mass. 



E,ub 8 grms. of carmine into a paste with water, add 

 about 10 grms. of strong ammonia and mix well, 

 then add about 100 c.c. of water, shake well and 

 £lter ; if a suction-pump is not used it will probably 

 take 10 to 20 hours to filter. Warm the filtrate to 

 about 40° C. Pour it then slowly into the gelatine 

 kept warm over a water-bath, stirring continuously ; 

 when the fluids are weU mixed, add gradually strong 

 acetic acid, stirring as before; when the smell of 

 ammonia becomes faint, use acetic acid diluted 

 5 to 10 limes, adding it until the mixture smells of 

 acetic acid. The mixture previously a lake red 



