86 



PRACTICAL HISTOLOGY. 



FlG. 48. Capped Bottle for 

 Balsam. 



the solvent is added until a fairly thin fluid is obtained. Perhaps 

 the best solvent of all is xylol. It requires nearly twice its volume 

 of xylol. Filter through paper. The balsam should be kept in a 

 " capped " bottle (tig. 48) instead of a 

 stoppered one. If it gets too thick, add a 

 little xylol. 



Dammar Lac (Klein). 



Gum dammar . . i oz. 



Gum mastic . . . ^ ,, 



Turpentine . . 2 ,, 



Chloroform . . 2 ,, 



Dissolve the dammar in the turpentine, 

 and filter ; the mastic in the chloroform, 

 and filter. Mix the two solutions and 

 filter again. 



There must be no moisture in the 

 bottles, and the mixture must be kept in 

 ' capped " bottles, else the chloroform will 

 evaporate. 



Xylol-Balsam. Dry ordinary Canada 

 balsam in a sand-bath, to drive off all the 

 moisture, and until it becomes vitreous. 

 If it be spread out in a thin layer in a tin 



vessel, this is usually accomplished in two hours or so, but the 

 balsam must not be overheated or change its colour and become 

 brown. Dissolve the dried balsam in an equal volume of xylol. 

 Perhaps this is the best form of balsam to use. 



Balsam, when prepared, should be kept in a glass bottle with a 

 ground-glass cap. 



To Place a Section on a Slide. By far the most convenient 

 method is to place the section in a basin of water. Hold the slide 

 perpendicularly by the edges in the left hand, plunge the slide into 

 the water until it is about three-fourths immersed, and with a 

 mounted needle pull the section on to the slide, and at the same 

 moment raise the latter out of the water. The section adheres to 

 the glass, and if it be folded at one end, dip this end in the water, 

 when it floats out quite flat. Do nob attempt to spread out the 

 folds on the slide by means of a needle. 



Hold the slide vertically to allow the water to drain off, and 

 remove with a rag or well-washed cloth the remainder of the water 

 close up to the section. 



It may be stained on the slide. After the staining is complete, 

 remove the surplus dye by means of bibulous paper, taking care, 

 however, that the section itself does not adhere to the absorbent 

 paper. 



