54 On Mounting. 



The section measures say about 1J inches by 1 inch, 

 some slides must be procured 3 by 2 inches and some 

 cover glasses 2 by 1 inches, these had better be of No. 

 3 thin glass. 



Having cleaned one of the slides, place some Canada 

 balsam on it and spread it out with the needle, to some- 

 thing near the size of the specimen, then take the cover 

 glass and pass it into the oil of cloves under the speci- 

 men, in the same way the copper lifter is used to smaller 

 sections ; lift the cover glass and keep the section in its 

 place, then drain off the superfluous oil by holding the 

 cover glass on filter paper, on lifting it fresh from the 

 oil it should be allowed to drain slowly from one corner, 

 then invert the cover glass with the section on it, place 

 a little Canada balsam at the lower edge, and lower it 

 gently into the Canada balsam on the slide ; this must 

 be done very carefully, as bubbles will be found here 

 and there, and the cover must be lifted a little and 

 lowered again, until they have all been driven out. It 

 is a tedious process but amply repays the trouble. 



The great drawback in this method is that the front 

 of the cover glass is covered with oil of cloves and can- 

 not be cleaned until the balsam sets, a matter of time 

 with such a large surface. It can certainly be sealed 

 up with Hollis' glue, but even then it is not safe and 

 requires a great many coats before the glue is suffi- 

 ciently strong to resist such pressure as is required to 

 clean the cover glass. 



With some tissues it is possible to use a large cover 

 glass as a lifter, and by allowing a large quantity of oil 

 of cloves to remain to draw it off on to the slide and cover 



