( 78 ) 



Five green mangos were weighed and placed under a glass bell jar, 

 through which a current of air free from carbonic acid was conducted 

 which afterwards was made to pass through a Liebig potash bulb. 



This latter was weighed daily and the 5 fruits only after the end 

 of the experiment. 



The 5 fruits weighed originally 1139.3 grammes 

 After 3 days 1121.3 



and therefore lost in 3 days 18.0 grammes 



The potash bulb increased during 



the first day by 1.712 grammes 



the second day by 1.276 ,, 



the third day by 1.570 



Or in three days 4.558 grammes 



The fruits gave off 4.558 grammes or 0.40% of carbonic acid in 

 three days. 



Just as in the case of bananas a mango fruit from a parcel having 

 practically the same initial maturity was daily analysed; and this 

 time the analysis extended with a determination of free and total 

 citric acid. I had previously stated that the acid in the mango 

 really was citric acid and that no other organic acid could be found 

 in it. 



I determined the free citric acid by titration with 1/10 normal 

 potash in the boiled fruit whilst the amount of total citric acid was 

 determined by extracting the boiled fruit with alcohol and precipitating 

 the citric acid in the alcoholic liquid by means of barium acetate. The 

 precipitate was filtered off, washed, incinerated and finally, I deter- 

 mined the carbonic acid in the ash which was of course equivalent 

 to the total citrate in the precipitate. The figures obtained follow 

 here. 



The yellow colouring matter, which is produced during the ripen- 

 ing process, shows the same reactions as the carotine from carrots, 

 the same spectroscopic appearance and in fact resembles it in every 

 respect. 



During the after-ripening the starch is transformed into sucrose, 

 which later on becomes hydrolysed and splits up into glucose and 

 fructose. In the beginning of the process the fruit liberates water but 

 this constituent increases afterwards owing to the combustion of the 

 carbohydrates. The citric acid is vigorously attacked and the decrease 

 in the acid taste during the after-ripening is not due to an increase 



