8 PRACTICAL BOTANY. 



Sections stained with alum or with Kleinenberg's 

 hgematoxylin are to be mounted in Canada balsam (or 

 Dammar). Those stained with the ammoniacal solution 

 are to be mounted in glycerine. 



Carmine. The two best preparations of carmine 

 are those of Beale and Thiersch : carmine possesses, 

 however, but little differentiating power. 



1. Beale's Carmine To prepare this 0'6 gramme of carmine is 

 dissolved in 2 c.c. of boiling solution of ammonia ; the solution 

 must then stand for an hour or so to cool, and to allow of the 

 escape of the superfluous ammonia ; to the solution are added 

 60 c.c. of distilled water, 60 grammes of glycerine, and 15 grammes 

 of absolute alcohol. The mixture must be allowed to stand for 

 some time ; it is then to be filtered. 



2. Thiersch's Carmine Four grammes of borax are dissolved 

 in 56 c.c. of distilled water ; to this 1 gramme of carmine is added, 

 and then twice its volume of absolute alcohol is added to the 

 liquid. After nitration the liquid is ready for use. 



Carmine readily stains the protoplasm and the 

 nucleus ; Thiersch's preparation is especially useful for 

 bringing out the structure of the nucleus. It can very 

 well be used for sections which have been previously 

 treated with picric, chromic, and osmic acids. The 

 time during which the section is to be exposed to its 

 action varies very much, as is the case with hsematoxy- 

 lin. The rule is in both cases, that the most satisfactory 

 results are obtained by a prolonged immersion in a 

 dilute solution. In case of overstaining, the section 

 may be washed for a moment in water, to which a trace 

 of ammonia has been added. 



Preparations stained with carmine are best mounted 

 in glycerine. 



