1894.] MICROSCOPICAL JOURNAL. 177 



In about a quarter of an hour the cement will have 

 hardened sufficiently to enable you to run a ring of 

 rather thin Miller's Caoutchouc Cement around the glass 

 circle without disturbing its position ; it is well to see 

 before ringing it that the cover is full of petroleum. 

 Should any have been removed by the brush or by evap- 

 oration, take a clean steel pin, dip it in the petroleum 

 and place it against the part of the cover- glass that re- 

 quires filling, when it will run under without there be- 

 ing any fear of forming air bubbles, and none will spread 

 on the glass slides. 



After having tried to mount this preparation without 

 success in every medium I thought of — pure balsam, bal- 

 sam dissolved in benzole, chloroform, etc., thus, dammar 

 and castor oil, I thought of trying petroleum oil and 

 found that it had no action on the preparation. Slides 

 that have been mounted for some months are as good as 

 on the day they were finished. 



It is well that I should mention here a turn-table that 

 has been invented for some years, but does not seem to 

 be well known. It is called the concentric turn-table 

 and is made by Aylward of Manchester, England, it is 

 composed of an outer ring which revolves on the inner 

 ring, each has two brass pegs, which, on turning the 

 ring, clip the slide whatever width it may be within cer- 

 tain limits, and must hold it absolutely central, so that, 

 on replacing the slide to finish, it always returns to a 

 central position. The slides nyist always, of course, be 

 the standard length of three inches. 



Scheme for Imbedding, Sectioning, Staining, and 

 Mounting. 



By W. S. miller, 

 madison, wis. 



Specimens may be fixed in Flemming's chromo-aceto-osmic 

 acid, 10 per cent nitric acid or a saturated aqueous solution of 



