77 
On the Preservation and Mounting of Microscopic Objects 
in Minute Tubes. By Dr. Guy. 
(Kead March 12tli, 1862.) 
The several modes of preparing^ preserving, and mounting 
objects for tlie microscope have been so thoroughly examined 
and so well described by competent writers, and the art has 
attained to such perfection in the hands of those who practice 
it_, that little, if anything, can remain to be said respecting 
any of the methods in common use. I, at least, have no 
suggestions to offer regarding them. But there is one mode 
of preserving and mounting objects for the microscope which 
appears to me to be deserving of the attention of the Society. 
I have some experience of it ; and I think that I may ven- 
ture to commend it, as combining perfect preservation with 
great ease of application, cleanliness, and satisfactory display 
of all the objects to which it is applicable. I speak of the 
preservation and mounting of objects in small tubes. 
I may premise that there is a small class of objects, of great 
importance in a practical point of view, which cannot be com- 
pletely identified without being examined under the micro- 
scope, and which, being actually developed in tubes of narrow 
bore, and not admitting of being detached from them, compel 
us to resort to some method of tube-mounting. I speak of 
the deposits of metallic arsenic and antimony which the 
chemist obtains in medico-legal analyses by Marshes method, 
and of the sublimates of mercury, of arsenic, and of arsenious 
acid, which he procures from the small fragments of copper 
foil coated with the metals mercury and arsenic, by the method 
of Eeinsch ; also of sublimates of arsenious acid obtained as 
crystals from the powder of white arsenic, or from the green 
aceto-arsenite of copper, of which we have lately heard so 
much. This small but important group of objects, obtained 
ip glass tubes of small bore, and, if necessary, perfectly pre- 
served by sealing the tubes at both ends in the flame of the 
spirit-lamp, have to be mounted in some convenient way for 
microscopic examination. I will begin by indicating one or 
two obvious modes of effecting this. 1. A card of the size of 
the usual microscopic slide has a circular opening punched 
out in the centre ; this opening is enlarged by side- cuts, so 
as to receive the tube and to support it at each end. A com- 
mon label, with a central circular opening to correspond with 
the hole in the card, is pasted at the back ; the tube is dropped 
upon it, and is secured in its place by a slip of paper crossing 
it at either end. A description of the specimen is then writ- 
