On Mounting. 49 



use, and when they get thick from evaporation a little 

 chloroform can be added. 



Both of these mounting fluids are used in the same 

 manner and one description will apply equally well to 

 each. Canada balsam is the one commonly used, as 

 the materials of which it is composed are very cheap, 

 while gum dammar is rather expensive. The Dammar 

 varnish is also sometimes apt to become cloudy after a 

 time and it is difficult to make. 



To MOUNT IN CANADA BALSAM OK DAMMAR YARNISH. 



The sections having been properly stained and 

 washed, are placed in methylated spirit to remove 

 some of the water, and then immediately transferred 

 to a small quantity of absolute alcohol in a watch 

 glass, and covered with another to prevent evaporation. 

 They should be left in this for about 10 minutes. 

 The absolute alcohol, which should be the strongest 

 sp. gr. -795, has a great affinity for water, and will 

 remove all that is in the sections. 



"When ready remove the sections one by one from the 

 absolute alcohol with a needle, and drain off as much 

 alcohol as possible by touching the section on the back 

 of the hand or on a piece of clean filter paper, the back 

 of the hand is the best, as some fibres from the filter 

 paper may adhere to the section, which when seen 

 under the microscope, will not improve the beauty of 

 the preparation; when sufficiently drained, without 

 being allowed to become absolutely dry, they are placed 

 in a vessel containing oil of cloves ; they will spread 

 out on the surface of the oil, and as the spirit evapo- 



E 



