Micro-organisms oi? Maple Sap l v -"' 



coming better developed at the top, with a moderately spreading 

 surface growth. Development along- the line of puncture was at 

 first filiform and then echinulatc. Cultures 10 days old or more 

 were often beset with scattered tufts of villous or plumose out- 

 growths usually more pronounced in the upper part of the 

 medium. 



Agar plates. — Colonies at 25 ° C. showed rapid growth. Those 

 at the surface were at first round, sometimes becoming slightly 

 irregular. In the early stages the surface was smooth, often 

 becoming contoured and papillate or developing moderate stria- 

 tions and concentric markings. These characters were not in- 

 frequently combined in the same colony. The elevation was 

 convex. The edge was at first entire or undulate, frequently 

 becoming lobate. The internal structure of surface colonies 

 showed all stages of variation from finely granular through 

 coarsely granular to grumose and, less frequently, reticulated. 

 The outer portion of many colonies was filamentous or curled. 

 Young cultures often showed an even outer ring well differen- 

 tiated from the body of the colony and consisting of motile chains 

 through which were thickly scattered granules. The appearance 

 suggested that which is often seen in very early stages of lique- 

 faction on gelatin plates, but there was no sign of liquefaction in 

 the agar. Young surface agar colonies 1 to 3 days old usually 

 showed active motility within the colony. Buried colonies first 

 appeared as brown lenticular bodies, often becoming irregular 

 with the interior deeply reticulated. 



Carbohydrate agars. — Cultures were made in shaken agar 

 tubes containing 2% lactose, dextrose and sucrose, respectively. 

 Just previous to sterilization 1% of a solution of azolitmin (one 

 gram of azolitmin to 16 cc. of distilled water) was added to the 

 tubes. The sterilized melted agar was cooled to 40 C, inocu- 

 lated with a 2 mm. loop of a 24 hour old culture, thoroughly 

 mixed by shaking and incubated at 25 ° C. 



In lactose litmus agar good growth developed and acid pro- 

 duction became evident during the first day. A heavy white film 



