652 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



into a rubber nipple. In fig. 153 is shown a section of tlic pipette. 

 1 is the rubber stopper by means of which air-tight connections are made 

 between the glass pipette 4 and the body of the holder 5« ; 2 is the 

 union by which the two parts of the pipette ha and 5b are held together 

 with the rubber diaphragm 6 firmly clamped between them. The screw- 

 control 3 acts as follows : by turning the screw to the right, the disk 7 is 

 lowered and the rubber diaphragm 6 made taut. Then a slight turn of 

 the screw 3 to the left will draw liquids into the pipette, and a corre- 



»o»t Rv-eac<\ o<q»*q««»i. 



Fig. 153. 



sponding turn to the right will expel them. The aluminium handle 

 enables the fingers to obtain a firm grasp, leaving the thumb free to 

 move the screw. 



Plates for Growing Germs in Quantity.* — E. C. L. Miller uses 

 enamelled pans 10 in. diam. and 1 in. deep. The cover consists of 

 a round piece of wire screen of i-in. mesh, bound round the edge with 

 tin. Over this wire mesh is placed a layer of cotton-wool, and over this 

 a disk of thick paper. Under the wire screen a braid of coil cotton 

 extends round the periphery. All these constituents are securely sewed 

 together. These plates are sterilised by dry heat in the usual way, and 

 afterwards melted agar poured on to form a suitable layer. Condensation- 



* Centralbl. Bakt., lte Abt. Orig., xlvi. (1908) pp. 731-2 (2 figs.). 



