1742 



Journal of Applied Microscopy 



Fig. 8. 



tube, constricted near its union with the test tube, 

 and cotton-plugged at its outer opening. The test 

 tube is also constricted below the lower end of the 

 cotton plug. 



Method. — Introduce the medium into the test 

 tube by means of the drawn-out funnel (f), replace 

 the cotton plug and sterilize as usual. Inoculate 

 the medium and connect the end (b) of the lateral 

 tube with the Kipp generator. Pass gas through 

 for fifteen to thirty minutes. In case gelatin or 

 agar are used stand the test tube in a water bath 

 at 40°C. while the gas is introduced. Now seal 

 first the test tube and then the lateral at their re- 

 spective constrictions in the flame. Similar ap- 

 paratus have been constructed by Exner, Buchner 

 and Roux. For agar, blood serum, and potato slant 

 cultures Liborius arranges the medium so that the 

 slanted surface is opposite the lateral tube. 

 Hueppe closes the test tube or flask (Fig. 9) containing the inoculated 

 medium with a doubly perforated rubber stopper. In one perforation rests 

 a glass tube (L) which reaches to the bottom of the flask, the other 

 holds the glass tube (A) containing at its lower curve a small amount of 

 mercury. 



Method. — Introduce hydrogen at (L); the air is forced out through (A). Hav- 

 ing passed hydrogen through the tube for from ten to twenty minutes, seal the 

 glass tube (L) in the flame. The mercury in tube A serves as indicator of the 

 changes in pressure, which may take place as the result of gas production by 

 the growing bacteria in the tube or flask. If this indicator is not desired, a short 

 glass tube is used in the place of tube (A) and when all the air is replaced by 

 hydrogen the glass tube is sealed in the flame. 



FraenkePs method (1888) : Into a test tube (Fig. 10) containing liquified 

 inoculated gelatin or agar, insert a doubly perforated well fitting rubber 

 stopper carrying two glass tubes ; one reaching to the bottom of the 

 test tube, the other to the lower surface 

 of the stopper. Cover the top of the 

 rubber stopper and test tube with an air- 

 tight layer of paraffin or sealing wax. In- 

 troduce hydrogen through the long glass 

 tube. When all the air is replaced by 

 the gas, seal first the exit and then the 

 entrance tube over the flame, and roll the 

 test tube until the medium is congealed. 

 For agar stick and stab cultures, 

 Blncher (1890) recommends the follow- 

 FiG. 9. ing method : 



