496 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
spirit, changed twice or thrice. After this, for 10-15 days in 90 per 
cent, spirit, containing 1/2-3/4 per cent, tincture of iodine some tinc- 
ture being occasionally added. Finally, in 90 per cent, spirit until all 
the iodine was removed. After this the objects were immersed in abso- 
lute alcohol, or stained en masse , or soaked in chloroform, &c., pre- 
paratory to imbedding for sectioning. The results from this method of 
fixing are said to be very satisfactory, and the staining with most dyes 
very good. 
Simple Cover-glass Holder.* — Dr. O. Zoth shows how a simple 
cover-glass holder can be made from a strip of brass or platinum foil. 
The strip of foil, 7 cm. long and 4 mm. broad, 
widens out to 1 cm. sq. in the centre (see fig. 81) 
where it is bent twice almost at right angles, 
and the free ends are provided with two grooves 
cut by means of a file. The thickness of the foil 
should be from 0 • 6 to 0*3 mm., so that it can be 
easily cut with an ordinary pair of scissors. 
(6) Miscellaneous. 
Improvements in Microscopical Technique.! 
— Prof. H. G. Piffard discusses some of the im- 
provements in microscopical technique, among 
which he mentions the use of the electric light 
supplied from the street main. In order to 
use this it is necessary to employ a Carpenter’s 
rheostat, which not only effects a uniform resistance and voltage, but 
affords critical illumination. The author has had made for him lenses 
specially corrected for the D line of the spectrum, and these are advan- 
tageous both in visual and photomicrographic work. The usefulness of 
monobromide of naphthalin as an immersion medium is referred to, and 
the author has had constructed for him, by H. R. Spencer of Buffalo, a 
monobromide immersion lens which works most satisfactorily, and also 
an achromatic condenser with N.A. 1*40, at about half the cost .of 
English condensers. After showing the advantages to be derived from 
using lenses and condensers of high aperture, the author proceeds to 
discuss various mounting media, the preference being given to liquid- 
ambar, the formula for which we give elsewhere. Clarifying media, 
such as the essential oils, are next referred to, and the important fact is 
pointed out that what is sold as oil of origanum is not such, but in all 
probability red oil of thyme. The author advises a thorough re-study of 
our clearing media. 
Gaseous Formic Aldehyde for Disinfecting Purposes.! — MM. R. 
Cambier and A. Brochet report the results obtained by using their 
apparatus for disinfecting places with gaseous formic aldehyde. The 
experiments were of two kinds, theoretical and practical, the former 
carried on under laboratory conditions, the latter in a room of 75 cubic 
metres (5 m. x 5 m. x 3 m., with two doors and three windows). In 
* Zeitschr. f. wiss. Mikr., xi. (1894) p. 149. 
f Medical Record N.Y., 1895, pp. 545-9. 
X Ann. de Microgr., vii. (1895) pp. 89-102. 
Fig. 81. 
