1888.1 MICEOSCOPICAL JOUENAL. 83 



glycerine ; and, proving interesting, they are laid aside unsealed only to be 

 found spoiled when next seen, or are ringed with varnish, without a cell, to 

 make a mount that will be short lived by reason of the running-in or splitting- 

 oft' of the cement. It is no more trouble to place such objects, and cover 

 them, in the gum and glycerine medium at first, than in plain glycerine ; 

 and then they are already mounted to begin with, and they can, as desired, 

 be washed off the next day, or be neglected for years without injury. 



The following points may be of use to those not accustomed to this instanta- 

 neous method of mounting. 



I. Use only sufficient of the medium. By a little care a drop of the right 

 size can be employed, so that the cover-glass will be supported to the edges, 

 but without enough surplus material to require the fussy procedure of clean- 

 ing off the excess. If any should require removal, leave it to be scraped off 

 with a knife after drying for a few hours, instead of washing it off at once 

 with water. 



3. Breathe on the slide, and also on the cover-glass, just before making 

 contact with the medium, to moisten the surface and thereby prevent entan- 

 glement of air bubbles. 



3. Plunge the object into the drop of medium by means of a needle, or of 

 a flattened lifter, without entangling air by unnecessary stirring ; and remove 

 with the needle point any bubbles that may be seen. Do not discard the 

 specimen if a few small bubbles be included, as they may disappear in 

 time. 



4. The object may be taken from glycerine, or from a watery fluid, or even, 

 sometimes, from diluted alcohol. Do not dry it enough to get air into the 

 tissues, but be careful not to carry too much of the medium with it, as it is 

 easy to introduce, in this way, enough water to make the medium too thin, 

 or enough glycerine to prevent its drying properly. 



=5. Keep, within reach, a bottle of carmine or hcematoxylin stain, the latter 

 being capable, probably, of most general application ; and try immersing in 

 a drop of it, on a slide or in a w^atch-glass, such objects as are likely to take 

 the stain promptly. Many delicate sections, or membranes, teased-out tissues 

 or fibres, secretions containing interesting physiological or pathological struc- 

 tures, etc., will be stained exquisitely by being dipped in this a few seconds, 

 on the way to the mounting medium, or at most by lying in it while the next 

 object is being examined. 



6. If the object be thin, no care is required after covering; but if thick, air 

 may possibly enter at the side by shrinkage in drying, which should be cor- 

 rected by keeping the mounts in sight a few days and applying, when re- 

 quired, a very small drop of the medium, not over but at one side of the in- 

 cipient air bubble, so that it will run in in place of the air. 



7. If the object prove valuable, but not otherwise, label and number it at 

 once, and record in a systematic catalogue anything important that may be 

 known about it. 



8. If properly managed, the slide will need no cleaning after the mounting 

 and labelling are finished. It should only require to lie untouched for a few 

 days while the gum is drying at the edge of the cover-glass. 



9. Any time, after a few weeks, months, or years, the slide may be placed 

 on a turn-table and a ring of shellac varnish or Bell's cement be added. This 

 will give a neat amber finish, and may keep the medium from distorting the 

 object or the cover-glass by shrinking too much, or from becoming too hard, 

 and granular, in case it has been incorrectly prepared or used. 



By adopting this method of preserving suitable objects that may come under 

 his examination, the busiest man may, in the course of years, prepare a val- 

 uable collection, without appreciable labor and almost without knowing that 

 he is doing it. 



