and Laboratory Methods. 



1753 





'ti- 



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Novy recommended his apparatus (Fig. 24) designed for cultivating anaerobes 

 in a hydrogen atmosphere, also for the pyrogallic acid method. 



Ucke (1898) manipulated Novy's apparatus (Fig. 24) as follows: Put 10 

 grams of dry pyrogallic acid into a small beaker, float this beaker in a larger one 

 (120 c. c. capacity) containing 50 c. c. of a 20 per cent, solution of potassium 

 hydroxid and stand the two beakers in the apparatus, so that the glass tube 

 reaching from the glass stopper nearly to the bottom extends 

 into the small beaker. At the last moment, when the apparatus 

 is ready to be put into the incubator, introduce 50 c. c. 

 of water through the long glass tube and turn the glass stopper 

 90°. This causes the small beaker to sink and the solution of 

 potassium hydroxid mixes with the pyrogailol. By this 

 manipulation the pyrogallic acid does not gel access to the 

 alkali until the apparatus is sealed up, hence it is a means of 

 economizing the oxygen absorbing power of the pyrogailol. 



Wright (1901) recommends the following modification : 

 Into a medium-sized test tube (see Fig. 33) containing the in- 

 oculated culture medium, push a sterile cotton plug well down. 

 By means of a pipette pour i/< c. c. of a saturated solution of 

 pyrogailol and 1 c. c. of a 50 per cent, solution of sodium 

 hydroxid upon the cotton plug. Seal the tube with a well 

 fitting rubber stopper with as little delay as possible. The 

 quantity of the reagents added is so small that there is no 

 danger of its running down along the side of the tube into the 

 culture medium. According to Wright this method can be 

 used successfully for all kinds of flasks and tubes. He lays 

 stress on the fact that the nutrient medium should be freshly 

 boiled and of alkaline reaction. 



Slupski (1901) uses the following modification for plate cultures : His appa- 

 ratus (Fig. 34) consists of a bell jar 15 cm. in diameter and 5 cm. high, ending 

 at the bottom in a ground glass rim 1^ cm. in width. The bell jar is placed 

 in a glass dish about 10 cm. high. On the bottom of this glass dish rests a double 

 plate. The outer plate (b) contains water and the inner (a) is designed for 

 pyrogailol. Over the double plate rests a tripod which supports the open 

 petri dish. 



Method. — Pour the inoculated culture medium into the open petri dish. Fill 

 plate (b) with water and heap plate (a) with dry pyrogallic acid (25 grams). To 

 this add 50 c. c. of warm distilled water. Replace tripod. Throw two pieces of 

 KOH (14 gms.) into the pyrogailol. Quickly put a blotter and black paper on 

 top of the tripod, upon which place the open petri dish, invert bell jar 

 (X) into glass dish (Y) and seal with a thin layer of paraffin. Then pour hot 

 paraffin three to four cm. deep into dish (Y) and when cooled and congealed pour 

 some liquid paraffin on top. Place the apparatus for about 50 hours in the re- 

 frigerator at a temperature of 5-6°C. in order to prevent any growth while the 

 absorption of oxygen is still in process. Then put it in the incubator. 



Ham?nerl (Vd^X) uses a mat of heavy cardboard, felt, or cellulose which he 



Fig 33. 



