M u mi oroanisms 01' M \ri.i-: Sap ; ' ,; l 



phenolphthalein in the cold with N'/ioo sodium hydroxid, and 

 a bacteriological analysis was made in order to determine the 



degree of success which had been attained in inoculation. The 

 sap was then placed in a thoroughly clean pan over a brisk, 

 (laming wood fire and evaporated to a volume of about I quart, 

 when it was transferred to a white agate ware basin and concen- 

 trated to a density of n pounds to the gallon as indicated by the 

 thermometer. It was the custom to determine daily the tempera- 

 ture at which water boiled in the laboratory, and to subtract 

 from 219 the difference between 212 and the boiling point found, 

 in order to arrive at the temperature at which evaporation should 

 be discontinued during that day. Provision was thus made for 

 fluctuations in the boiling point due to atmospheric conditions. 



The sugar season of 1910 opened unusually early, before 

 the laboratory was quite ready for use. The first run occurred 

 on March 3 and 4, but the experimental trees were not tapped 

 until March 6. 



series 4: sirups 27 to 40 



The sap for this series was collected March 7, and placed 

 in the incubating buckets in 16 quart portions. It was not so 

 thoroughly mixed as to insure absolutely uniform chemical com- 

 position, but was handled in a manner to secure approximate 

 uniformity. The temperature of all except two of the samples 

 was raised to 40 C. before placing them in the incubator. One 

 of these was allowed to stand outside where a temperature of 

 o° to io° C. prevailed, while the other was heated to 8o° C. 

 and placed in the incubator. These two samples, together with 

 one of those heated at 40 C, constituted the controls. When the 

 temperature of the sap had dropped to 28 C. the samples were 

 inoculated with their respective organisms and incubated for 3 

 days. Evaporation of the samples began at 9 a. m., March II, 

 under conditions which made it possible to average the produc- 

 tion of a sirup in an hour and a quarter. The temperature of 

 incubator mav be seen bv reference to figure 5. 



