272 



Transactions of the Society. 



Description of Anaerobic Apparatus 

 (Text-fig, Fig. 1). 



The apparatus used consists of a glass gas-jar, the lower part 

 of which is filled with an inverted bottle and surrounded with 

 small lengths of glass tube, and filled up with a 10-p.c. solu- 

 tion of pyrogallic acid in caustic potash to the level of the bottle. 

 The lid is zinc, with a rubber washer, and kept in position by 

 fly-nuts fixed to a broad brass trap encircling the upper part 

 of the jar. Through the lid is screwed and soldered a brass 

 T-piece ;• the ends of the T carry small pieces of rubber pressure- 



f»~ 



Tte- 



FlG. 1. 



tube, which are clamped up with screw-clamps when _ the jar is 

 exhausted. The plates or tubes, sown with the material contain- 

 ing anaerobic organisms, are placed in the jar, the lid firmly 

 fixed with the fly-nuts, and the air exhausted with a water-pump, 

 shown on the left side of the illustration ; some time is allowed to 

 elapse after the column of mercury in the manometer has reached 

 its highest level Ca perfect vacuum, of course, is not obtained by 

 the water-pump, owing to the vapour tension of the water)^ to allow 

 of the air dissolved in the media to be removed ; when this is judged 

 to have occurred, hydrogen is allowed to flow in from the cylinder, 



