148 



PRACTICAL HISTOLOGY. 



the excess of staining fluid, which would otherwise 

 he precipitated, and are transferred from this to 

 spirit (absolute alcohol is gene- 

 Fig'- 25 - rally recommended, but strong 

 methylated spirit is sufficiently 

 anhydrous) in which they are 

 allowed to lie until it is certain 

 that all the water is replaced 

 (live minutes is generally amply 

 sufficient), after which they are 

 placed in oil of cloves for a 

 minute or two. In this the 

 sections should almost imme- 

 diately become clear and trans- 

 parent, and the change has at 

 the same time the effect of caus- 

 ing their color to appear darker. 

 If any parts of the section do 

 not participate in the change of 

 appearance, but remain opaque 

 and cloudy, it is a sign that all 

 the water has not been extracted, 

 either because the sections were 

 not left long enough in spirit, or 

 because this was not anhydrous 

 enough (for oil of cloves will not 

 mix with water nor with alcohol 

 which contains more than a trace 

 of water). But it is not too late 

 to put them from the oil into 

 strong spirit again, and when 

 they have been long enough 

 there to transfer them once more 

 to oil of cloves. All these trans- 

 ferences may be effected by aid 

 of a section-lifter (Fig. 25), made 

 from a piece of copper or i>'ernian- 



Section-lifter. Natural * . 



size. silver wire flattened out at one 



or both ends, which are bent 



over so as to be hoe-shaped. l>y means of this in- 



