On Mounting. 47 



is not folded in any part. Lay the slide on some filter 

 paper, and with needles spread out the tissue to its 

 fullest extent, without stretching it. It is necessary to 

 be very careful of this, as if the tissue be a serous mem- 

 brane, stained with silver, the outlines of the cells will 

 be completely destroyed wherever it has been stretched. 

 In the same way, non- striped muscle fibre in the me- 

 sentery of the newt, will be broken up and quite ruined. 



When the tissue appears to be extended in a natural 

 manner, without folds, take up the slide and wipe off 

 all moisture from it with a clean cloth, if there is a 

 large quantity on the specimen, some may be removed 

 with a bit of filter paper, but great care must be taken 

 not to touch the specimen itself with the paper as it 

 will adhere to it ; at the same time it must not be 

 allowed to become dry, and if this seems probable, it 

 can easily be moistened by breathing on it occasionally, 

 until the cover glass is ready. Take up a clean cover 

 glass and place a drop of glycerine on the centre, invert 

 and place it horizontally on the specimen, leaving the 

 weight of the cover glass to spread out the glycerine. 

 If there is an excess of glycerine round the edges of the 

 cover glass, it must be removed by placing small pieces 

 of filter paper in contact, which will soon absorb the 

 superfluous fluid, but must not be left too long or they 

 will drain it from under the cover glass. When suffi- 

 cient has been taken up by the pieces of filter paper, 

 remove them and wipe the slide with a dry cloth, tak- 

 ing care to clean off all glycerine without touching the 

 cover glass. 



When this is done the preparation must be sealed, by 



