( 82 ) 



ment unreliable. Moreover it might well be that the decay was not 

 only to be ascribed to the exclusion of oxygen bnt to the hindered 

 evaporation which would be injurious to the fruit. 



In order to elucidate this point, a few bananas were placed in a 

 tube, through which a current of nitrogen passed, while at the 

 same time some other bananas from the same part of the bunch 

 were kept in the ordinary atmosphere. When the latter had become 

 yellow, tender and ripe, those in the nitrogen tube had still retained 

 their green appearance. The analyses of the peeled fruits of the two 

 parcels yielded these figures. 



Moisture 



Insoluble in alcohol. 

 Soluble in alcohol. 

 Sucrose 

 Reducing sugars 



It followed then, that the after-ripening in the air had gone on 

 uninterruptedly whilst the fruits kept in the nitrogen atmosphere 

 had remained unchanged and had preserved their starch content ; so 

 that free access of oxygen is an indispensable condition for the 

 saccharification of starch in the fruit. 



The following experiments were undertaken with a view to ascer- 

 taining whether this saccharification was brought about by a vital 

 process or by the action of some diastatie ferment present in the fruit. 



A jelly consisting of isinglas and agar agar of such a compo- 

 sition that it was solid at the ordinary temperature was mixed with 

 l°/ of starch, poured into a series of Petri dishes and sterilised. 

 Slices of green mango and banana fruit or pieces of half ripe tamarind 

 fruit were placed on the stiff jelly in some dishes and on that of 

 others figures and letters were traced with a pencil dipped in mango- 

 juice. After two, or sometimes more, days the particles of fruit were 

 removed and the jelly covered with a very dilute solution of iodine 

 in potassium iodide which after having remained there for a minute 

 was washed off'. In every case not only the spot where the fruit 

 had been placed or where the pencil strokes had been applied, remained 

 Avhite, but all round a white stain spread out, lined with a red 

 border which gradually faded into the surrounding blue coloration 

 of the still unattacked starch. The longer the dishes had been allowed 

 to stand, the larger was the white stain. In every one of these cases, 



