378 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Two very simple Microtomes.* — Mr. E. Pinnock describes two very 
convenient and cheap forms of microtome. (1) The “handy” has a 
Y-shaped groove for the paraffin imbedded or the naturally hard object, 
the latter being moved forward by a finely cut screw, the object being 
held in place by the thumb. There is a flat expansion at the end for the 
razor, which should preferably be ground flat. (See fig. 66.) 
Fig. 66. 
Fig. 67. 
(2) Dr. Wetherill’s application of the well-known rivet principle to a 
hand-microtome. It is made of hard wood, with a horizontal portion as 
a guide for the sweep of the razor, and an incline upon which slides the 
rider or object- carrier, to which the paraffin imbedded object is attached 
by melting. In the case of a naturally firm object, the rider may be 
dispensed with. The object is moved up the incline by the thumb of the 
hand holding the microtome. (See fig. 67.) 
C4) Staining- and Injecting-., 
Contrast-Staining of Bacteria. f — Herr Knaak has devised a method 
in which the cells are stained with fuchsin, and the bacteria w r ith 
methylen-blue. After the action of the methylen-blue, the preparation 
is decolorised with hydric sulphide solution (1-10). By this procedure 
the pigment is not removed, but merely reduced, and much less so in 
the bacteria than in the cells and nuclei. In order to prevent reoxida- 
tion of the leucomethylen-blue by the atmospheric oxygen, the pre- 
paration is treated with saturated tartaric acid solution. It is then 
contrast-stained with fuchsin (1 part saturated alcoholic solution to 
20 parts water) for 5-10 seconds. Instead of sulphuretted hydrogen 
solution, 1 per cent, solution of argonin may be used for decolorising, 
but this must be allowed to act for 4 minutes. 
Simple Method for Staining Spores.f — Dr. A. Aujesky has devised 
the following procedure for staining spores. The cover-glass film, dried 
in the air, is placed for 3-4 minutes in almost boiling 1/2 per cent, 
hydrochloric acid. On removal, the cover-glass is washed in water, 
dried, and then stained with Ziehl’s fuchsin solution, after the manner 
of staining tubercle bacilli in sputum. That is to say, some fuchsin 
* Trans. Amer. Micr. Soc., xix. (1897) p. 189 (2 figs.). 
t Deutsch. med. Wochenschr., 1897, No. 42. See jCentralbl.^Bakt. u. Par., 
1“ Abt., xxiii. (1898) p. 343. 
Centralbl. Bakt. u. Par., xxiii. (1898) pp. 329-31. 
