758 



SUMMARY OF CURRKNT RESEARCHES RELATING TO 



All Btages in the evolution of the amoebae were able to be followed 

 out in the cultivation plates. 



For staining purposes the methods of Laveran and of Marino were 



used. 



New Bacteria Filter.* — F. Kern describes a new bacterial filter. 

 As seen from the accompanying illustration (fig. 178) it consists of a 

 porcelain cup, the bottom of which is perforated and holds the filter 

 candle, with the blind end upwards and the open end fixed into the hole 

 in the bottom of the cup ; beneath this there is a connecting pipe that 

 leads into the lumen of the candle ; the cup, candle and connecting pipe 

 are made out of one piece of porcelain; the cup and pipe are glazed ; 

 by means of a rubber cork the connecting pipe can be attached to a 



vacuum flask. When the cup is full of the 

 fluid to be filtered, the candle is covered 

 by a glass bell, shaped like the candle but 

 rather larger ; by this means the action of 

 the vacuum is not hindered by the air that 

 would otherwise be drawn in above the 

 filtering level of the candle, and it is not 

 essential that the cup should be completely 

 full of fluid. The author claims that it is 

 a simple contrivance, being composed only 

 of one piece of porcelain and a glass globe, 

 both of which can be readily cleaned and 

 sterilised ; that it will filter relatively small 

 quantities of fluid ; that it is inexpensive. 



Pure Culture from Cells Isolated under 

 the Microscope.f — S. L. Schouten obtained 

 pure cultures from single cells isolated under 

 the highest powers of the Microscope, by 

 means of fine glass needles controlled by 

 a special mechanism. The apparatus em- 

 ployed is represented in fig. 179 as £ natural 

 size. It consists of A an iron plate stand- 

 Fig. 178. ing on four feet ; the Microscope is fixed 



by a ring to the square copper plate B, 

 and can be moved by means of a screw to the right or left or back- 

 wards or forwards. Of the Microscope there is shown the stage F, the 

 Abbe condenser G, the iris diaphragm H, the mirror I, the foot J, and 

 the objective K ; on the stage is a moist chamber, the " isolation 

 chamber," which has a special construction, the right and left sides 

 being provided with horizontal clefts, which can be closed by thick 

 oil ; through these clefts are passed two needles M, to be described 

 below. On to the moist chamber, which can be moved by means of a 

 mechanical stage, is brought the cover-slip, on the under side of which 

 the isolation will take place. The needles are provided with handles N, 

 resting on the copper bar 0, which can turn about a pivot P, and at the 



* Centralbl. Bakt.. 1«« Abt.. xxxix. (1905) p. 214. 

 t Zeitachr. wiss. Mikrosk., xxii. (1905) p. 10. 



