Micro-organisms of Maple Sap 



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the sirups of this scries, with the exception of number 28, seemed 

 to have been very largely produced by the tluorescent group of 

 organisms. Even the cold control was apparently considerably 

 injured both in color and flavor by the organisms developing in it 

 during the incubation period, so that the depreciation in quality 

 due to their action is probably greater than is indicated by the 

 figures given above. 



That this supposition is well grounded is shown by the re- 

 sults obtained in later series. 



SERIES 5 : SIRUPS 41 TO 48 



Following the run obtained on March 7, there was a freeze 

 and no considerable amount of sap was obtained again until 

 March 14. The sap was gathered with a team and a sufficient 

 quantity for 8 samples was withdrawn as soon as it reached the 

 sugar house. Six of these were heated to boiling and placed in 

 the incubating buckets while two were left unheated, their tem- 

 perature being very near o° C. On the morning of March 15, 

 five of the heated samples were inoculated and allowed to in- 

 cubate for 3 days at temperatures indicated in the graph (figure 



10 



ti 



cc 



JS 



50 

 15 



r° 



Fig. 6. Graph of incubation temperatures for series 5 ; saps 41 to 48 in- 

 clusiye. The arrow heads on next to the bottom line from left to right indi 

 cate respectively the time of inoculation, the time of evaporation of the lirsi 

 sample and the time of evaporation of the last sample. 



6). Before evaporation the samples were titrated, plated, and 

 sampled as described for the previous series. 



41 Number 41 was a control left standing over night be- 

 fore being made into sirup on the morning of March 15 when 

 it contained 66 organisms per cc. and reacted i% N/100 acid. 



