672 
SUMMARY OP CURRENT RESEARCHES. 
stay of some minutes in tlie steriliser immediately before use. This 
procedure practically diminishes the trouble arising during sterilisation 
from a large air-bubble in the closed end of the tube. 
Modification of Koch’s Method for making Gelatin Plates.* * * § — 
Dr. L. Heydenreich finds that it is more convenient to reverse Koch’s 
method and place the ice-pan above the gelatin to be cooled. The same 
kind of tripod-leveller is used. 
Widal’s Reaction with a Measured Quantity of Blood.} — Dr. 
R. L. Pitfield has found by experiment that a disc of filter-paper 
(Schleicher and Schiill’s 598) 8 mm. in diameter will absorb 1 ccm. of 
blood from a drop on the finger. If dried, the blood may easily be dis- 
solved out in 10 ccm. of water, bouillon, salt solution, or bouillon culture 
of typhoid, and thus a dilution of one to ten of the blood obtained. 
New Procedure for Inoculating Animals with Rabies Virus.} — 
Dr. J. Lebell recommends the following procedure which possesses all 
the advantages and none of the disadvantages of trepanning and sub- 
dural infection. The fixed virus is injected into the spinal canal. An 
ordinary Pravaz syringe is used, and the needle inserted between the 
spinous processes of the first and second lumbar vertebras. Two or 
three drops of an emulsion of the fixed virus is sufficient. The injection 
site should be freed from hair, disinfected with a one per thousand sub- 
limate solution, and after inoculation covered with collodion. The 
rabbit dies on the seventh or eighth day. If the procedure be properly 
carried out there are no complications. 
Black Anilin Ink.§ — Dr. L. Heydenreich gives the following for- 
mula for preparing anilin black ink which combines chemically with 
fibres and does not fade. (A) Crystallised copper chloride 4 ; sodium 
chloride 5 ; ammonium chloride 3 ; distilled water 30. (B) Anilin 
hydrochlorate 40 ; gum arabic 15 ; water 95. The two solutions must 
be kept apart and in the dark. When required for use equal bulks are 
mixed together. If one solution only be preferred, then, before mixing 
with solution A, 100 hydrochloric acid is added to solution B, and the 
whole boiled for some time. Though intended to dye filter-papers so as to 
contrast with white or coloured fibres in the filtrate, the ink may be used 
for other articles, such as linen. Filter-papers are to be soaked in the 
ink for two days, dried, steamed for 10-15 minutes, washed in soapsuds, 
and finally in distilled water. 
* Zeitschr. f. wiss. Mikr., xvi. (1899) p. 153 (2 figs.). 
+ New York Medical Kecord, 1899, i. pp. 659-60 (1 fig.). 
j Centralbl. Bakt. u. Par., l te Abt., xxvi. (1899) pp. 221-2. 
§ Zeitschr. f. wiss. Mikr., xvi. (1899) p. 177. 
