56 PARASITIC AMOSB.E OF MAN. 



that during the first staining with eosin a deep red 

 color be obtained as otherwise it will all be removed 

 by the methylene blue solution. 



The Hoematoxylin-Eosin Stain. Sections may 

 be stained by this method and give fairly good results. 

 They should first be fixed in Zenker's solution and 

 then imbedded in paraffin. The solution of hsema- 

 toxylin used is that known as Delafield's and is pre- 

 pared as follows : 



Four grams of haematoxylin crystals (Grubler's) 

 are dissolved in 25 c.c. of 95 per cent, alcohol and to 

 this is added 400 c.c. of a saturated aqueous solution 

 of ammonia-alum, the mixture then being allowed to 

 stand in an unstoppered bottle exposed to the light 

 and air for four days. It is then filtered and to the 

 filtrate is added 100 c.c. of glycerine and the same 

 amount of 95 per cent, alcohol. This solution is 

 allowed to stand in the light until it has a deep purple 

 tinge, when it is filtered and stored in a tightly stop- 

 pered bottle. If the purple tinge is lost the solution 

 is no longer suitable for staining. 



In using the stain for section work the sections 

 are stained in it for 30 minutes to an hour, or more, 

 and are then washed in several changes of water or 

 in running tap water for from 10 to 30 minutes. 

 After they are thoroughly washed, an aqueous solu- 

 tion of eosin of y 2 per cent, strength is used for a 



