26 



The Plant World. 



viously published work shows no appreciable diiTerence in the 

 distribution of this invertase in the date as regards apical, middle 

 or basal end, or outer, inner or tannin zones. The rapid inversion 

 of the sugar must then be induced by the increased mobility of 

 the sugar, due to mechanical disintegration of the tissues, and 

 to free exposure of their intracellular invertase. Mechanical 

 injury does not release or render mobile this intracellular in- 

 vertase in the sense that it releases sugar and soluble nitrogen- 

 ous compounds, although treatment of the fruit over night with 

 acetic acid vapor renders its invertase readily soluble in glycerol. 



A quantity of green fruit was ground and crushed rapidly 

 with a meat cutter. The juice running from the mill was filtered 

 at once, to remove the pulp. The pulp was then pressed as 

 rapidly as possible in a Buchner press and the juice obtained at 

 various pressures kept separately. 



1st Experiment; fruit immature: 



The inverting power of these portions as determined by 

 mixing 75 c. c. juice, 75 c. c. water and 20 grams cane sugar, was 

 as follows : 



The portion obtained under low pressure, when fresh, can 

 not be filtered clear through paper, but after standing shows con- 

 siderable sediment. The inversion was with the turbid juice 

 and undoubtedly due to the small amount of insoluble matter 

 present. 



2nd Experiment; same date, more mature. 



