Micro-organisms of Maple Sap t63 



apparently feed mainly on the proteids and mineral salts and exert. 

 a detrimental influence on color and flavor. Generally speaking, 



the yeasts and molds, which often but not always thrive well 

 in a slightly aeid medium, together with the spore-bearing bac- 

 teria, had the most pronounced inverting action on sucrose, either 

 through the production of invertase, or by the formation of 

 acid, or both. In many cases they likewise seriously affected 

 color and flavor. 



Most of the remaining bacteria used in this work did not 

 prove particularly active as invert sugar makers, but their harm- 

 ful effect was in many instances manifested by the color ami 

 flavor of the sirup. 



Discission op tiik Total and Insoluble Ash and Malic 



Acid Values 



A survey of the analytical data given in tables 16 to 34 shows 

 that the ash and malic acid values of 34 of the samples examined 

 were slightly below the standards used in determining the purity 

 of maple products. These deficiencies have been noted in the 

 discussion of the several groups. The question now arises 

 whether these abnormalities, which in many cases are very slight, 

 are due : 



(1) To the exceptional conditions obtaining in these ex- 

 perimental trials of the manufacture of sirup from sap, e. g.. 

 the small amounts of sap evaporated, the small number of trees 

 contributing to the individual samples, and the variation in den- 

 sit} of the resulting sirup. 



(2) To the treatment of the sirups after manufacture 

 and previous to analysis. 



(3) To the effect of the inoculating organisms on the 

 physical characteristics and chemical composition of the sirups. 



These considerations have been clearly explained in the 

 preceding pages, but their connection with the analytical data 

 under discussion has not been traced. 



For the purpose of easy reference and to assign, if possible. 

 a definite reason for these failures, all samples showing deli- 



