558 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
were applied some hours before the beginning of an attack, and one of 
these, opened 24 hours later, was found filled with red corpuscles in- 
closing living plasmodia and mobile pigment ; the other leech was 
opened 48 hours after sucking, and the appearances seem to have been 
quite similar. A leech applied 24 hours after treatment with quinine 
was found to contain a few shrunken plasmodia and a little immobile 
pigment. 
It would seem therefore that the malaria parasites can be kept 
alive within the leech for at least 48 hours, and this retention of life 
suggests that the leech might be employed for studying the life- 
history of the plasmodia. It would he satisfactory to ascertain if the 
blood drawn by the leech were capable of infecting other animals. 
The author suggests that human blood rendered artificially coagu- 
lable by leech substance might be used as a cultivation medium for 
malaria parasites. 
Tubercle Bacilli and other Pathogenic Micro-organisms found in 
the Sputum and Lung Cavities.* — Mr. S. Kitasato obtains pure or ap- 
proximately pure cultivations of tubercle bacilli from the sputum by 
making the patients, after having well washed out their mouths, ex- 
pectorate into capsules filled with sterilized water. The sputum must 
be coughed, not merely hawked up. The selected lumps are then 
washed ten times successively in so many vessels filled with steri- 
lized water. Cultivations are then made on agar and often these 
are quite pure. It was remarked, however, that cultivations from 
the sputum differ at the outset of their growth from those obtained 
from tuberculous organs. For the first two weeks they appear as 
circular white opaque flakes on the surface of the agar, and the 
colonies are furthermore distiuguished by being moist, smooth, and 
shining (almost like colonies of white yeast) while those from the 
organs are dry, dull, and wrinkled. 
By about the fourth week these differences disappear, the two sets 
of colonies becoming indistinguishable. 
The author then goes on to state that most of the bacilli in the 
sputum and in the contents of lung cavities are dead, although micro- 
scopically they are exactly alike. This was proved both by cultivation 
and injection experiments. 
From observing the constant association of other bacteria and 
their presence in considerable numbers, the author concludes that 
these other micro-organisms exert some influence on the disease, but 
to what extent is uncertain. 
Preparation of Sterile Gelatin Tubes. f — In their researches on the 
chemical bacteriology of sewage, Sir H. E. Roscoe and Mr. J. Lunt 
prepared gelatin tubes in a manner which they say is simpler and 
shorter than that generally adopted. The test-tubes, 5 or 6 in. X f, 
are first washed and set up on end to drain, and then heated to 150° 
for an hour. Pure cotton-wool is placed in a steam sterilizer and 
subjected to a current of wet steam for two hours, and afterwards dried 
in the hot-air sterilizer by heating to 150° for half an hour. This 
* Zeitschr. f. Hygiene, xi. (1892) pp. 441-4. 
t Phil. Trans., 182 B (1892) pp. 662-4. 
