Micro-organisms of" Maple Sap 589 



sodium carbonate, potassium permanganate, pyrogallic acid in 

 i'/o sodium hydroxid, and distilled water and allowed t<> pass 

 for 2 hours through a Novy jar containing freshly prepared agar 

 slants. The jar was sealed and held at room temperature. No 

 strain showed growth after 5 days incubation, but in all cases 

 good growth occurred in from 1 to 2 days after the seal was 

 broken. A second series incubated for 10 days gave duplicate 

 results. In addition to the plain agar slants, lactose and dex- 

 trose agar slants were used with similar results. The reaction 

 of the incubated agar medium was roughly determined by tritur- 

 ating 5 cc. of the solid medium in 45 cc. of distilled water and 

 titrating. Sufficient carbon dioxid had been absorbed to give 

 the cold medium a reaction of +20 Fuller's scale. 



In order to be sure that the failure to grow in the carbon 

 dioxid was not due to the acidity of the medium, augmented by 

 absorbed carbon dioxid, the following anaerobic methods were 

 employed. 



Hydrogen method. — A series of plain agar slants and a 

 series of 1% dextrose litmus agar slants were placed in a Now 

 jar and the air displaced by hydrogen. The jar was exhausted 

 in order to hasten the displacement. The litmus agar remained 

 neutral, and titrations of the plain agar controls without boiling 

 demonstrated that the reaction had not been changed. No 

 growth occurred in 10 days. All developed well when removed 

 from the jar. 



Roux method. — Sterilized Roux tubes were aseptically filled 

 with young broth cultures of the 13 strains. This test was tried 

 several times and in no case did growth appear except in de- 

 fective tubes or in those containing air bubbles. After incuba- 

 tion of 10 days the tubes were broken and the contents gathered 

 in sterile test tubes where normal growth resulted. 



These tests show that the various strains are strictly aerobic. 

 They further indicate that lactose and dextrose are not fer 

 mented in the absence of oxygen. (Consult papers of Andrewes 

 and Ilordu (1) and Glenn (to) in bibliography). 



