APPENDIX. 3S1 



^carmine dissolved) will become an opaque carmine 

 red (carmine in suspension). Add a few drops of 

 thymol, remove from the water-bath and let cool ; 

 if it does not smell of acetic acid when again melted, 

 a little more of the acid should be added. 

 The gelatine mixtures must of course be injected warm ; 

 the blood should be washed out of the organ to be 

 injected with warm salt solution; during the in- 

 jection warm salt solution should be poured over the 

 organ or the whole animal should be immersed in 

 warm salt solution. The injected tissue should be 

 placed in alcohol. 



c. Prepare gelatine as in (6). Take 100 c.c. of a 2 p.c. 

 solution of Berlin blue warmed to 40" 0. and pour it 

 slowly into the gelatine kept warm on a water-bath, 

 stirring continuously. 



Chemical Eeagents. 



Millon's reagent. 



Weigh out 50 grms. of purified mercury and an equal 

 weight of pure strong nitric acid. Place the mercury 

 in a flask in the closed chamber, add the nitric acid 

 to it, and leave the mixture as long as any chemical 

 action continues. If all the mercury is not dissolved 

 warm it gently to complete the solution. 



Add then to it twice its volume of water, and place 

 aside for some hours ; a white crystalline precipitate 

 will fall ; the supernatant fluid is Millon's reagent. 



Pehling's fluid. 



(1) Dissolve 103-92 grams of pure cuprio sulphate in 

 warm water and add water to make up exactly a 

 litre. 



