170 



Tannic Acid Fermentation 



Comparison of fermentative capacity in an infusio.n of gall nuts. 

 For the investigation an extraction of the gall nuts was made as 

 follows: 1800 grams of the Aleppo gall nuts were placed in one jar 

 and the same quantity of Chinese nuts in another. To each were 

 added 3 liters of tap water, and the extraction was allowed to 

 continue for five days, when the extract was filtered. To each 

 jar were added again 2 liters of water, and after one day the ex- 

 tracts were filtered and combined with the previous filtrates. Then 

 the two extracts from the Chinese and Aleppo galls were mixed. 

 After a second filtration the solution was ready for the culture 

 vessels. For this purpose cultures were made in the usual way, 

 using Erlenmeyer flasks of 150 cc, each, with 50 cc.of the infusion, 



TABLE IV. 



CULTURE NO. 



DURATION 



TANNIC ACID 



IN CULTURE 



SOLUTION 



LOSS OF 

 TV^NIC ACID 



GALLIC ACID 



IN CULTURE 



SOLUTION 



GAIN OF 

 GALLIC ACID 



DRY 



WEIGHT OP 



FUNGUS 



Check 



1.637 



1.797 



Penicillium sp. 



A comparison of the two organisms, as regards their fermenta- 

 tive capacity, shows again that Aspergillus niger is a more efficient 

 organism. Note especially that in four days the Aspergillus cul- 

 tures exhibit an increase of gallic acid nearly four times as great 

 as that in the Penicillium cultures, and all of the tannic acid had 

 been converged in the former by the eighth day, while in the Peni- 



