480 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
glass tube is fitted on a rubber tube with clamp. The tube is then 
pulled down a few centimetres. The clamp on the tube is then 
opened, and the agar runs through into some suitable recipient. The 
glass tube must be lowered from time to time as the agar descends until 
the whole of the clear fluid is removed. On account of the relative 
waste of material it is not advisable to make the apparatus smaller. 
Simple Method for isolating Bacteria on Agar and Blood-Serum.* 
— Prof. G. Banti fills the ordinary test-tubes and tubes 2-3 cm. wide 
with the requisite quantity of agar, and allows it to set obliquely, the 
condensation water running to the bottom. The material to be examined 
is then diluted with a few ccm. of bouillon or sterile water, and 1, 2, or 3 
drops of the mixture placed in the condensation water of three tubes or 
more, according to the dilution of the material, or the number of bacteria 
present, which of course must previously be determined by microscopical 
examination. In some cases, of course, it is not necessary to dilute the 
material, but it can be placed straight away in the condensation water. 
When the two ingredients are mixed by shaking gently the condensation 
water is allowed to flow over the agar surface, and then the tube placed 
upright in the incubator. This simple procedure is said to possess all 
the advantages of plates without their inconvenience. 
Centrifuging Agar.j — Dr. C. S. Haegler uses a centrifuge for pre- 
paring agar; by this procedure the clarifying is shorter and simpler 
Fig. 73. 
than clearing gelatin. The centrifuge is driven by water-power, and 
to the stem is screwed on a plate (fig. 74 b ), having a lid fastened on 
* Centralbl. f. Bakteriol. u. Parasitenk., l te Abt., xvii. (1895) pp. 556-7. 
t Tom. cit., pp. 558-60 (2 figs.). 
