248 INSTANTANEOUS MOUNTING. 



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 haematoxylin 

 stain, the latter being capable, probably, of most general applica- 

 tion ; and try immersing in a drop of it, on a slide or in a watch- 

 glass, such objects as are likely to take the stain promptly. Many 

 delicate sections, or membranes, teased-out tissues or fibres, secre- 

 tions containing interesting physiological or pathological structures, 

 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 corrected by keeping the mounts in sight a few 

 days and applying, when required, a small drop of the medium, 

 not over but at one side of the incipient 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 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 gra- 

 nular, 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 a few years, prepare a valuable collection, without 

 appreciable labour and almost without knowing that he is doing it. 



