ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



491 



cultivated in the presence of leucocytes (guinea-pig, dog, rabbit, man), 

 not only live but develop, while the leucocytes degenerate. The 

 leucocytic exudate is placed on ice for a day and then centrifuged, and 

 the supernatant fluid used as cultivation medium. Pus from abscess of 

 the liver is sown in the fluid. Intestinal mucus is not very suitable for 

 the purpose, but if necessary, must be injected into the peritoneal sac of 

 a guinea-pig. This gets rid of most of the contaminating bacteria, and 

 the peritoneal fluid may then l)e used for cultivation. Cultivated in 

 this way, ama?btc have all the known characters of the human parasite. 



New Method of Isolating Bacillus typhosus from Infected 

 Water.* — AV. J. Wilson describes a new method of isolating B. typltosus 



m>//.'////^///;,////;a^/// /////////////////////// ^A^ 



Fig. Si. 



(fig. 84) from suspected water, which, according to ordinary standards, 

 might be deemed free from pollution. The principle of the method is 

 to evaporate water under reduced pressure. 



A is a water bath maintained at 37-40° C. This temperature can 

 be easily obtained by regulating the height of the flame of the Bunsen 

 burner. No special gas regulator is required, though Reichert's may be 

 used with advantage. In the bath are two Winchester quart bottles 

 containing the water to be examined. Eubber corks fit into the necks 

 of these bottles, and should be so shaped that they will not be driven in 

 when the pressure in the interior of the bottle is reduced. These corks 

 are perforated by glass tubes which project into the interior of the 

 bottles. The surface of the water should be at least 4 in. from the end 



* Brit. Med. Journ., 1907, i. pp. 1176-7 (1 fig.). 



2 K 2 



