1:86 Bulletin \(>y 





of surface growth developed and during the third day gas pro- 

 duction began. This continued to increase in amount for a few- 

 days and then ceased. The reaction remained acid and at no time 

 was there evidence of reduction of the litmus. 



In dextrose litmus agar the growth was more rapid than in 

 agar containing lactose. The acid production was more pro- 

 nounced and the gas formation observed was greater than was the 

 case with either lactose or sucrose. Signs of bleaching at the 

 surface appeared on the fifth day and progressed rapidly till the 

 entire contents of the tube assumed a pale yellowish hue. The 

 f< nination of a layer of liquid above the surface film of growth 

 was noted in most of the tubes under observation. 



In sucrose litmus agar tubes the organism developed ven 

 much as in dextrose tubes except that the growth and the various 

 characters were slightly less pronounced, or at best developed a 

 little later. 



Gelatin. — All gelatin media contained 10% of Nelson's 

 photographic gelatin No. I and was of such a consistency as to 

 remain firm at 25 C. Gelatin cultures were incubated at 20 C. 



Gelatin stroke. — Gelatin slants showed a beaded growth along 

 the line of inoculation, frequently becoming filiform or echinu- 

 late, sometimes developing into a broad band with roundly dentate 

 margins and spreading beneath into an arborescent growth. After 

 a few days a fine filamentous outgrowth developed beneath the 

 surface under the stroke and extended several mm. into the body 

 of the gelatin. In some series this growth finally became arbo- 

 rescent while in others this character failed to develop to an ap- 

 preciable extent. Liquefaction of gelatin began on the eighteenth 

 day, and proceeded very slowly thereafter, becoming complete in 

 about three months. 



Gelatin stab. — Stab cultures in gelatin showed best growth 

 at the top. The line of puncture was beaded, the beads soon 

 united to form a grannlose mass with a villous border developing 

 into long capillary fibers extending nearly to the walls of the 

 tube. These fibers eventually developed fine lateral branches, 





