Micro-organisms ob M \ri.i-: Sap ;, 'b~> 



was introduced into the tree about 4 inches to one side of the 

 original wound. Great care was observed to secure for this 

 tap-hole as entire freedom from infection as was possible with- 

 out special apparatus, and sterile spouts and buckets were em- 

 ployed. At the time of retapping, the sap in the sour bucket 

 was emptied but the receptacle was not washed. In this way 

 two samples of sap were obtained from the same tree at the 

 same time, one of which was relatively free from micro-organ- 

 isms, while the other was heavily infected. These two saps were 

 concentrated to sirup under practically identical conditions and 

 submitted to the same subsequent treatment as were the other 

 >irups. These experiments were intended to show whether the 

 changes which have been demonstrated to occur in sap near the 

 close of the season were due entirely to the action of foreign 

 organisms, or whether thev should be ascribed in part or in en- 

 tirety to physiological changes within the tree. 



METHOD OF SIRUP SCORING 



At the close of each season the sirups which had been made 

 during the preceding weeks were scored for flavor by a com- 

 mercial expert who was entirely unfamiliar with their history. 

 A series of numbered beakers of uniform appearance were placed 

 on a table and each received a few ounces of the sirup correspond- 

 ing in number to that of the beaker. The expert tasted the 

 sirups and assigned each to its respective grade. After the 

 entire series had been scored, and a record made of the results, 

 the samples were rearranged in such a way as to insure the loss 

 of their identity, except by the small number on each beaker, and 

 the judge was asked to regrade them. In cases of special im- 

 portance the samples were repeatedly disarranged and passed 

 back to be regraded. Incredible as it may seem they were in- 

 variably placed in the grades originally assigned them and usually 

 in the same relative position within the grades. Not a single 

 instance of contradiction occurred among the entire 12S samples. 3 



'The Station is under obligation to Mr. Otto Ludwig 0!' Burling- 

 ton for his invaluable and experl assistance. 



