and Laboratory Methods. 



1743 



Fig. 11. 



Reverse the inoculated test tube (see Fig. 11), remove 

 the cotton plug ; with the open end downward dip the test 

 tube into a beaker containing a solution of diluted glycerin 

 (equal parts glycerin and water). By means of glass tube 

 (g) introduce hydrogen into the test tube. In about five 

 minutes all the air is replaced by the gas, the generator is 

 disconnected, and the beaker containing the test tube is put 

 into the incubator. 



Hesse (1890) modified Blucher's methods by inverting 

 the inoculated test tube into mercury instead of glycerin. 



Fiuhs (1890) rejects the condensation water from slanted 

 blood serum tubes, inoculates the slanted surface, reverses 

 the tube and introduces hydrogen for about five minutes. Without changing 

 the position of the test tube he then inserts a tightly fitting, sterilized rubber 

 stopper and seals hermetically by dipping the sealed part of the tube into liquid 

 paraffin. 



Ogata (1892) used a method very similar to that of Liborius. Instead of in- 

 troducing the gas through the lateral tube as Liborius did, Ogata does away with 

 the lateral tube and conducts the gas down into the medium by means of a capil- 

 lary glass tube running through the cotton plug of the test tube down to the bot- 

 tom of it (see Fig. 12). The air is slowly forced out of the tube in form of gas- 

 bubbles, some of which collapse, others form foam. As 

 soon as the foam has passed up through the narrow part of 

 the tube, the capillary tube is removed and while there is still 

 foam in the upper portion of the tube the constriction is 

 sealed over the flame. 



Heim (1892), who claims to be the inventor of this 

 method, recommends that, except when Esmarch roll cultures 

 are made, the test tube should be sealed without removing 

 the capillary tube ; that the inoculation should be made be- 

 fore the tube is constricted, and that the constriction should 

 not become wet, as the glass is liable to crack during the 

 operation of sealing in the flame. 



For liquid medium Roth (1893) used an upright flask 

 (see Fig. 13). In the lower part of the neck rests a cotton 

 plug, which is attached to a wire running out through the 

 flask. Through the cotton plug passes one end of a glass 

 tube, the other being conducted into a cup of glycerin. 



Method. — Fill the flask about half full with liquid me- 

 dium, press the cotton plug (c) well down into the neck, 

 push the glass tube down near the bottom of the flask and 

 connect the other end of it with the gas generator. When 

 all the air is replaced by the gas, and before disconnecting 

 the apparatus from the generator, raise the glass tube out of 

 the medium as shown in Fig. 13, immerse the other end of 

 Fig. 12. the glass tube in glycerin, fill the neck above the cotton 



