554 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
to set obliquely. In order to avoid entrance of germs when the fluids 
were mixed, the author mixed them before sterilizing the serum. The 
serum, which is stained brown from the haemoglobin, can be used very 
well for plate cultures, and for this purpose it is recommended to use 
equal parts of blood-serum and meat-pepton-agar. The plates inocu- 
lated with some loopfuls of gonococcus pus show, when kept at the body 
temperature, in 24 hours, in addition to many other colonies, very small 
whitish-yellow points, which by the third day after inoculation have 
become so great that their characteristic irregular form can be descried 
with the naked eye. Magnified fifteen times, the deep-lying colonies 
are seen to be sharply defined, of irregular shape, and with many pro- 
longations. The colour of the colonies is brownish and is due to optical 
causes and not the result of the presence of pigment. The growth of 
the deep-lying colonies is slow and ceases at the beginning of the second 
week when they have attained the size of a pin’s head. The superficial 
colonies form pretty regular glassy scums with sharp irregular margins. 
On oblique media the colonies look like glassy drops 12 hours after 
inoculation. 
Permeability of the Chamberland Filter to Bacteria.* — M. E. de 
Freudenreich records his observations on the permeability of the Cham- 
berland porcelain bougie filter to bacteria. The same subject has been 
dealt with by other observers, notably Kitasato, Kiibler, Giltay, Aberson, 
and Miquel. The author’s apparatus was very simple, and consisted in 
placing the bougie inside a vessel filled with the infected fluid and 
filling the exhaust pipe close to the filter with cotton wool. The ex- 
periments were of two classes, those in which the fluid was bouillon 
infected with enteric fever bacteria, and water. Several experiments 
with the typhoid cultures showed that no bacilli passed through ; cul- 
tivations made with the fluid drawn through remained quite sterile. In 
the second series water was filtered through at 35°, at 22°, and at the 
ordinary temperature of the room. In the first instance bacteria were 
cultivated from the filtered water passing through on the sixth day ; in 
the second on the tenth day ; while in the third it was sterile on the 
twenty-first. It is obvious therefore that germs do pass through, and 
that temperature plays an important part. For practical purposes there- 
fore it is necessary that the filter should be sterilized once a week. 
Plate Method for cultivating Micro-organisms in Fluid Media. f 
— Dr. P. Drossbach has devised a method for obtaining pure cultures. 
The principle consists in having a number of patches of nutrient 
material on one plate and infecting each plot with a very dilute solution 
of the fluid to be examined. The plates are made of stout glass in 
which are pressed or ground out a number of depressions from 2-3 mm. 
deep. The plates are about 100 sq. cm. in size and it is convenient to 
have plates with 3, 5, 9, and 16 depressions to the sq. cm. Plates 
which are not to be exposed to a high temperature are easily made by 
pouring paraffin in Petri’s capsules to form a layer 3 mm. thick and 
when the paraffin has become cold making the necessary depression with 
a cork-borer or other tool. 
* Arm. de Microgr., iv. (1892) pp. 559-68 (1 fig.). 
f Ceatralbl. f. Bakteriol. u. Para^itenk., xiii. (1893) pp. 455-7. 
