27 



semi-solid at 15° C, and is perfectly fluid at 18° C; i. e., the meltin-ic point has l)een 

 rednced (> to S deirrees, indicating a partial peptonization. 



The most rapid liquefaction obtained was witli a .streak culture on 

 stock 205. It was inoculated with a large loop from a fluid culture 

 10 days old and was kept at 18^ to 24^ C. On the twelfth day there 

 was a thin, pale-yellow streak 2 to 3 mm. wide and 5 cm. long, in the 

 middle part of which there was a small hole containing fluid g-elatin. 

 This liquefaction began the ninth or tenth day with a slight sinking 

 in of this part of the streak. On the twentieth day the liquefaction 

 involved about one-fourth of the gelatin (10 c. c). On the twenty- 

 ninth da}' fully three-fourths of the gelatin was fluid and there was a 

 copious pale-yellow precipitate (temperature since last record, about 

 22° C). Not until the thirty-ninth day was all of the gelatin fluid. 



All of these gelatins contained some muscle sugar, which may have 



slightly retarded liquefaction, since various writers have shown for a 



numlier of bacteria that small doses of grape sugar retard and large 



ones prevent liquefaction. 



2N 

 In stock 208 (stock 205 + enough -j- c. p. HCl to make it neutral 



to sensitive neutral litnuis paper) there was no growth whatever at 

 10° C. This inoculation was a streak the whole length of a long slant. 

 It was made with a large loop of fluid from a beef -broth culture 7 

 days old and well stocked with living germs, as shown by the result of 

 concomitant inoculations into other media. This culture was kept 

 under ol)servation 22 days. Inasnuich as the organism grew well in 

 stock 205, and will also grow at 10° C, the failure of this tulje was 

 ascribed to the sodium chloride developed in the gelatin by the addi- 

 tion of the HCl, enough being produced to give a feeble taste of salt. 

 (See p. 13.) 



In the + 20 gelatin (stock 244b) this organism and Fs. phaseoU 

 behaved nuich alike, both growing very much better than Pd. 

 campestris. 



In poured plates (+ 20 gelatin in Petri dishes) the buried colonies 

 were round, roundish, or ellipsoidal, with smooth margins. No spin- 

 dle-shaped colonies were seen and none or few having rough, irregu- 

 liir margins. (See plate cultures under Nutrient Agars.) 



The si/e of these buried colonies in densely crowded ])lates (2,00() to 

 3,000 colonies per held of Zeiss 16 nun. aprochromatic and 12 com- 

 pensating ocular), after 5 days at 13° to 16° C, was usually 16 by 16/^ 

 or 16 by 20//. Some, however, were smaller, and others were as large 

 as 24 by 24/< or even 28 l)y 32/^. The colonies were nearly colorless 

 and very finely granular, with margins sharply defined and free from 

 irregular outgrowths. Occasionally there were queer looking com- 

 pound colonies i-t^sulting apparently f rf)m the growth of tlu^ coiuponent 

 meml)ers of small /.oogloiac. The jilates were distinctly clouded to the 



