36 Bacterial Disease of the Mango 



side of which was placed a small heap of dry pyrogallic acid. The whole 

 was next put inside the Bulloch's apparatus, the bell jar carefully sealed 

 on to the ground glass plate and the air partially exhausted from the 

 apparatus by attaching the exit tube to a suction pump. A strong 

 solution of KOH was then siphoned into the glass basin without 

 admitting air, dissolving the pyrogallic acid. A strong alkaline solution 

 of pyrogallic acid was thus formed which absorbed the oxygen and 

 carbon dioxide within the bell jar. 



The apparatus was kept at a temperature of 30° C. with a number 

 of control tubes. In 48 hours there was a very vigorous growth in all 

 the control tubes; the growth in the tubes deprived of oxygen was 

 exceedingly slow as compared with that in the controls, and was not 

 at all abundant. 



This experiment was repeated a number of times with similar 

 results. 



Hydrogen. A set of cultures was prepared and placed in the 

 Bulloch's apparatus as described in the previous experiment. In this 

 case, however, hydrogen was generated, and after being purified by 

 passing through wash bottles containing solutions of silver nitrate, 

 potassium permanganate and potassium hydrate, it was allowed to 

 stream through the apparatus until all the air was expelled. Any 

 oxygen or carbon dioxide remaining in the bell jar was absorbed as 

 before with an alkaline solution of pyrogallic acid. 



The growth in the tubes in the atmosphere of hydrogen was slightly 

 better than in those kept in an atmosphere composed chiefly of nitrogen. 

 This was found to be the case in two successive experiments. 



A set of tubes inoculated from hydrogen cultures and grown in 

 Buchner's tubes in the absence of oxygen made better growth than the 

 cultures deprived of oxygen which had been made direct from aerobic 

 cultures. 



Carbon dioxide. The apparatus was prepared in the same way as 

 before and a current of carbon dioxide passed through it. In this case 

 any remaining oxygen was absorbed by means of a solution of pyro- 

 gallic acid in water. There was a slight growth in all the tubes at 

 the end of 48 hours, but not quite so much as in those grown in an 

 atmosphere of hydrogen. Growth was abundant in all the control 

 tubes. 



Sulphur dioxide. In this case S0 2 was passed through the apparatus 

 until all the air was displaced before the introduction of the KOH 

 solution. There was no growth in any of the tubes, nor did any growth 



