172 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
a half. After having been cleaned and boiled in the usual way, the 
potatoes are, when cold, bound round with twine and suspended close 
together. They are then immersed in shellac solution thrice at intervals 
of half an hour. In the course of another hour they are quite dry, and 
may be stored away for future use. 
Examining Rectal Mucus for Tubercle Bacilli.* — According to 
Dr. Sawyer, it is useful for diagnostic purposes to examine the mucus 
from the rectum if there be no sputum, or if tubercle bacilli cannot be 
demonstrated in the pulmonary excreta. The author quotes three cases 
in which he found tubercle bacilli in considerable numbers in the rectal 
mucus, but none elsewhere. 
Simple Method for the Sero-Diagnosis of Enteric Fever.f — Prof. 
E. Pfuhl takes a drop of blood from the ear and mixes it in the hollow 
of a slide with ten times the quantity of water. This not only dilutes 
the blood, but gets rid of the red corpuscles. To the serum is then 
added an equal quantity of a bouillon culture of typhoid bacilli. This 
is done by dabbing the culture on a cover-glass and inverting it over the 
serum in the ground- out slide. 
Improvement in the Sedgwick-Rafter Method for the Microsco- 
pical Examination of Drinking Water 4 — The Sedgwick-Rafter method, 
now extensively employed in America for the analysis of drinking 
waters, is, says Mr. D. D. Jackson, as follows : — A definite quantity of 
water, usually 250 ccm., is filtered through Berkshire sand placed in a 
funnel. The size of the grains is such that while they will pass through a 
sieve of 60 meshes to the inch, they will not through one having 120 to the 
inch. The organisms adhere to the sand, while the water passes through 
a hole at the bottom of the funnel closed by fine bolting cloth. The sand 
is dropped into a test-tube containing 5 ccm. of sterile water. The tube is 
then shaken and the water decanted with another test-tube. The micro- 
organisms are distributed by blowing into the water with a pipette, and 
1 ccm. removed to a cell 50 mm. long by 20 mm. wide and 1 mm. deep. 
The Microscope is graduated so that each field examines one cubic 
millimetre of water. The improvement made by the author consists in 
altering the shape of the funnel, which has a diameter of 2 in., and a 
length to the beginning of the slope of 9 in. The length of the slope is 
3 in. The leg of the funnel is 2J in. long, and its internal diameter 
1/2 in. The lower end is closed by a rubber plug, perforated by a 
small hole, and the latter covered with fine bolting cloth. Above the 
plug is a layer of fine sand about 3/4 in. thick. 
The most important errors to which this method is liable, says Mr. 
G. 0. W hippie, § arise from the concentration of the sample. These are 
(1) the funnel error, or that caused by the adhesion of the organisms to 
the sides of the funnel ; (2) the sand error, or that caused by the organ- 
isms passing through the sand ; (3) the decantation error, or that caused 
by the organisms adhering to the particles of sand, and by the water 
used in washing the sand being held back by capillarity during decan- 
* Med. News, May 23, 1896. See Centralbl. f. Bakteriol. u. Parasitenk., l te Alt., 
xxi. (1897) p. 71. 
t Centralbl. f. Bakteriol. u. Parasitenk., xxi. (1897) pp. 52-7. 
t Teclinol. Quarterly, ix. (1896) pp. 271-4 (1 ph). § Tom. cit., pp. 275-9. 
