344 SUMMARY OF CURRENT RESEARCHES RELATING TO 
If the staining has been successful, the membrane is pale blue, while the 
protoplasm and its connections are blackish blue. 
Rapid Method of making Permanent Specimens from Frozen Sec- 
tions by the Use of Formalin.* — The method described by Dr. T. S. 
Cullen is as follows : — A piece of the fresh tissue is sectioned on an 
ether freezer, and the sections placed in 5 per cent, solution of formalin 
for 3-5 minutes, then in 50 per cent, alcohol for 3 minutes, and in 
absolute alcohol for 1 minute. Wash in water; stain in liEematoxylin 
for 2 minutes ; decolorise in acid alcohol ; rinse in water. Stain with 
eosin ; transfer to 95 per cent, alcohol ; then pass through absolute 
alcohol, creosote or oil of cloves, and mount in balsam. 
Or as an alternative method, should it be desired to retain the blood 
in the sections, a piece 1x5x2 cm. is placed in 10 per cent, formalin 
for 2 hours, after which the procedure is as before. 
(3) Cutting-, including Imbedding and Microtomes. 
Simple Microtome for Biological Work.| — Mr. A. Flatters de- 
scribes an improved form of the simple microtome originally designed 
by him. The carrier is moved upwards in the cylindrical well by a 
screw carrying at its lower end a notched disc, against which works 
a clicking arrangement ; three of these discs with different numbers of 
notches may be used, so that sections of any desired thickness may be 
cut. The aperture of the razor plate is, on the under-side, of the same 
diameter as the well, but on the upper side it is slightly less, this being 
for the purpose of firmly holding the imbedded mass in position as it is 
screwed up. The razor plate, which is held in position over the well by 
a clamp, may be swung on one side to enable the uncut material to be 
removed. For larger or longitudinal sections a special razor plate, 
with a rectangular aperture and a corresponding holder, may be fitted to 
the instrument. 
(4) Staining and Injecting. 
Simple Method for Contrast-Staining Micro-Organisms.* — Dr. Clau- 
dius stains microbes on covers and in sections by the following pro- 
cedure. The reagents used are (1) 1 per cent, aqueous solution of 
methyl-violet ; (2) 1 vol. of saturated aqueous solution of picric acid 
plus 1 vol. of water ; (3) chloroform ; (4) oil of cloves. 
Cover-glass prejjarations are stained in the methyl-violet solution 
for 1 minute, washed in water, mopped up on blotting-paper, immersed 
in the picric acid solution for 1 minute, washed and mopped up again, 
then decolorised in chloroform, and, after having been dried, mounted 
in Canada balsam. Sections are stained and treated very similarly, but 
the two solutions are used for two minutes instead of one ; and, after 
having been very carefully mopped up, are decolorised by means of oil 
of cloves, after which they are passed through xylol, and then mounted 
in balsam. Twenty-six species were tried by this method : 17 were 
stained and 9 were not ; among the latter being B. typhi, B. coli com., 
Sp. cholerse asiat., Pneumobac. Friedlaenderi. 
* Bull. Johns Hopkins Hosp., viii. (1897) pp. 108-9. 
t Pharmaceutical Journ , lviii. (1897) pp. 485-6 (4 figs.), 
f Ann. Inst. Pasteur, xi. (1897) pp. 332-5. 
