294 DE. VINCENT HAERIS. 



of the first solution were allowed to remain upon the dried 

 blood for about five minutes, and were then washed off with a 

 gentle stream of water from a wash-bottle. The cover-glass 

 was then dried in the flame of a spirit-lamp and allowed to 

 cool. When ready for the second dye, a small quantity was 

 dropped upon the cover-glass and allowed to remain the same 

 length of time. A second washing with a stream of distilled 

 water followed until the washings were all but colourless ; dry- 

 ing and mounting in Canada balsam concluded the process. 

 Treatment with alcohol and clove oil previous to mounting in 

 several instances quite vitiated my result, and so I gave up 

 that method of dehydration and clearing. In cases where I 

 thought it possible to employ three dyes, the third was used in 

 a manner almost exactly similar to the one described above. 

 The method of fixing the corpuscles with osmic acid did not in 

 the least improve the staining of the corpuscles. The chief 

 precaution which appeared to be necessary was not to allow the 

 blood to coagulate, and to place it under conditions of rapid, 

 but natural, drying, e. g. in the sun's rays. 



Arrangement of the Combinations of Colours : 



Series A. — Primary colour, red; tried with orange, yellow, 

 green, blue, violet, and brown. 



1st Dye. 2nd Dyes. 



Substances used. Substances used. 



Red — Yellow — Aailin Primrose. 



Fuchsln — Lake. Orange — Tropseolin, or Auriu. 



Rosein — Crimson. Green — Iodine Green. 



Eosiu — Pink. Blue— Methylen Blue. 



Violet — Hoffman's. 

 Brow n — Bismarck. 



Series A. 



iled and orange. (Eosin and aurin.) 

 This combination was unsuccessful, as the solution of aurin 

 had to be made with absolute alcohol, it being such a very in- 



