542 Journal of Agricultural Research voi. xviii, no. io 



SUMMARY 



(i) The invertase activity of the spores of blue aspergillus, Aspergillus 

 niger, and Penicillium expansum is exhibited at concentrations of sugar 

 varying from lo to 70 per cent. 



(2) The maximum invertase activity of those mold spores occurs 

 between 50 and 60 per cent concentrations. 



(3) An increase in the number of mold spores is responsible for in- 

 creased invertase activity in a saturated sugar solution. 



(4) The leastnumberof spores of Penicillium expansum and Aspergillus 

 nigcr required per cubic centimeter to produce inversion in saturated sugar 

 solution is between 50,000 and 110,000. About 5,000 spores of blue 

 aspergillus are needed to cause inversion. 



(5) The evidence that mold spores alone are capable of deteriorating 

 cane sugar is corroborated by the data herein presented. 



