270 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
C 5) Mounting', including- Slides, Preservative Fluids, &c- 
Method for Hermetically closing permanent Cultivations of Bac- 
teria.* — When cultivations of bacteria are intended for exhibition in a 
museum, the culture-vessels should be hermetically closed. This is 
usually done with rubber caps or paraffin. The disadvantage of the 
former is that they become hard and brittle, and the latter may, if the 
weather become hot, get soft and so sink down. 
The method recommended and devised by Dr. C. F. Dawson, 
which obviates the foregoing inconveniences, is as follows. The cotton- 
wool plug is cut off flush with the top of the tube with a pair of hot 
scissors. A circular sterilized cover-glass is then pressed in on the top 
of the wool so that it just touches the rim of the tube. A thin cake of 
gelatin which has been lying in perchloride (1-1000) for a short time is 
then spread firmly over the top and held in position by a rubber band. 
When the gelatin is nearly dry the superfluous gelatin and with it the 
rubber band is cut away with a knife. Thus the test-tube is covered in 
with a circular layer of gelatin, and when this is dry it is further pro- 
tected with a varnish composed of the following : — alcohol, 200 parts ; 
white shellac, 90 parts ; balsam of copaiba, 8 parts. 
Medium for Mounting Microscopical Objects which will not 
mould.']' — Dr. A. M. Edwards has devised a medium of high refractive 
index, and suitable for mounting animal and vegetable objects. 
It consists of a mixture of saturated solutions of borax, real salicylic 
acid, and oil of cinnamon. The mixture is filtered. The proportions 
are not given. 
Influence of the Composition of the Glass of the Slide and Cover- 
glass on the Durability of Microscopic Objects.^ — Herr R. Weber, in 
view of the destruction of microscopic objects through defect or excess 
of alkalinity in the glass of the object-holder or cover-glass, recommends 
for delicate preparations a glass especially rich in lime, having a com- 
pos tion very similar to that of window-glass. 
Mr. G. S. Marryat’s Form of Mounting and Dissecting Stand. — 
The following note by Mr. F. M, Halford was read on Feb. 15th : — 
“ There is nothing new about the simple framework of this stand, which 
consists of a 3/4 in. pine base-board, 2 ft. 8J- in. by 11 in., on which 
are raised, in the position shown on plan annexed, two 3/4 in. oak upright 
supports for the stage and arm-rests. These uprights are grooved at 
various levels as shown, and the arm-rests are carried down diagonally 
from the uprights to the base-board. 
The stage is 4J in. by 4J in., and of glass, either transparent 
or opal. When dealing with transparent objects the light is reflected 
from a small square mirror inclined to the necessary angle and laid on 
the base-board immediately under the stage. If it is desirable to 
moderate the light, a square piece of oak with diaphragm of the required 
diameter is inserted in one of the lower grooves. Four thick elastic 
* Centralbl. f. Bakteriol. u. Parasitenk., xii. (1892) pp. 720-1. 
t Reprint from ‘ The Omaha Clinic,’ Sept. 1892. 
t Zeitschr. f. Inetrumentenk., xii. (1892) p. 388. See Chem. Ber., xxv. (1892) 
p. 2374. 
