GuY^ on preserving Microscopic Objects in Tubes. 81 
the flame of the spirit-lamp^ it retains its form of a flat oval^ 
and presents under the microscope a surface so slightly 
curved as to diffbr little (for all practical purposes not at all) 
from the surface presented by the flat microscopic glass. I 
send round specimens of this tubing corresponding with those 
I have already shown from the round tubing. This oval 
tubing is sold for two-and-sixpence a pound, and the cost of 
each minute tube must be exceedingly trifling. 
I have now said enough on the subject of tube-mounting as 
applicable to chemical sublimates ; and at this point I might 
perhaps be reasonably expected to stop. But though my 
own practical interest in the question ceases here_, I was un- 
willing to leave my paper imperfect by omitting to indicate, 
and to illustrate by specimens, some of the more obvious non- 
chemical applications of the method of preserving and mount- 
ing objects in tubes. Let me premise that I am not about to 
recommend this method as better than those now in use ; I 
speak of it merely as a convenient, simple, easy, and cleanly 
method, suflicient for every purpose of identification, if not 
of display. Requesting you to bear this in mind, I wdll pro- 
ceed to indicate some of the objects to which the method is 
applicable. 
1 . In the first place it is important, not only in the case of 
those chemical substances which I have spoken of as obtained 
in small tubes for practical purposes — I mean sublimates of 
arsenic, antimony, mercury, arsenious acid, &c. — but also in 
the case of the more volatile chemical substances, such as 
camphor, sulphur, and iodine, which we may wish to examine 
by preserving them in sealed tubes, also of such crystals as 
those of corrosive sublimate, which undergo rapid decomposi- 
tion when exposed to the air. 
2. Again, the method is obviously applicable to the preser- 
vation and display of round and flat seeds, the flat tubes being 
used for both, or the round tubes for round seeds, and the 
flat tubes for flat seeds. It is equally applicable to the pre- 
servation and display of such objects as pollen and starch. 
3. The method is also convenient for such small cylin- 
drical objects as the antennae of insects, and the stamens and 
pistils of most plants. Some of these objects are very 
delicate, and are both distorted and spoiled, if flattened. 
4. The method of tube-mounting is also obviously applic- 
able to the preservation and display of minute insects. 
5. Lastly, the flat tubes, obtained from the oval tubing 
or cane, may be used for any purpose to which the ordinary 
modes of mounting are applicable. I speak, however, only of 
mounting in the dry. I have no experience of the use of 
