ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



467 



vesuvin solution heated for 1-1^ minutes. By this method the granules 

 and the bacterial body are more deeply stained than by the Neisser 

 method. 



(6) Miscellaneous. 



New Fermentation Tube.* — A. Bobin devised the apparatus which 

 is shown in the accompanying illustration (fig. 101). The side tube c is 

 packed with non-absorbent cotton ; the arm A of the (J tube is filled with 

 mercury ; the tube B is filled with the culture, and then the rubber 

 stopper holding the side tube c and the straight tube d is tightly in- 

 serted. When this is done, the end of d which serves for the escape of 

 air displaced by the stopper is sealed in the flame. The gas generated in 

 B escapes into A, displacing the mercury. To determine the C0 2 ratio, 



Fig. 101. 



Fig. 102. 



the tube B is filled up to the rubber stopper. Two fermentation tubes 

 are used. In one the arm A is filled with mercury, and the other with a 

 saturated solution of sodium or potassium hydrate, this being readily 

 accomplished by inclining the \J tube. The C0 2 passing through the 

 caustic solution is absorbed, and the unabsorbed gas (H) is left ; from 

 this the ratio is easily determined. 



Bottle for Cedar Oil-t — In Schuberg's bottle for keeping cedar oil 

 the stopper has two grooves (a a in fig. 102), so that any excess may 

 drain downwards. This prevents the oil from running over the neck 

 and making the outside greasy. A glass cap fits over the neck. When 

 travelling, the stopper should be replaced by a cork. 



PP 



* Proc. Soo. Amer. Bacterid, 1900. See Centralbl. Bakt., 1" Abt., xxix. (1901) 

 491-2 (1 fig.). J t Zeitsokr. f.angew. Mikr. vii. (1901) pp. 45-6 (1 fig.). 



2 i 2 



