346 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



of the above agars, as well as in plum agar. In three days at 24 C. 

 there was fine growth at surface of medium in each case, but no growth 

 deep in medium in tubes and no indication, at any time, of gas forma- 

 tion. The walnut organism seems to be a strict aerobe. 



Litums Agars. The walnut organism was also grown on litmus lac- 

 tose, litmus galactose, litmus dextrose media and litmus saccharose. 

 This was made up as follows: Distilled water, 2 per cent Witte's pep- 

 tone, 0.5 per cent (c. p.) sodium chloride, 2-J per cent agar, and 2 

 per cent of the above-named sugars; titration was plus 12 Fuller's 

 scale. In three days at 23 C. there was abundant growth along the 

 line of puncture and over surface. The cultures in galactose after 

 seventy days showed slight reddening of the agar near the bottom of the 

 tube, but not nearly so decided a reaction as was secured with the olive 

 organism, Pseudomonas olem (Arc.) Trev. In the litums dextrose and 

 litmus lactose there was no visible change in color of medium, even after 

 two months' growth. 



Gelatin. Ten per cent gelatin and beef peptone bouillon was used. 

 After twenty-four hours at 20 C. there was a slight yellowish growth 

 along the line of puncture. Liquefaction begins within a short time at 

 the surface. The type of liquefaction is crateriform (Chester's termi- 

 nology) , the liquefaction being at first restricted to the mouth of the stab 

 and forming a deep pit. As growth continues the liquefaction extends 

 laterally, and in about five days the upper portion of the gelatin in the 

 test has become liquefied and would be termed stratiform. However, 

 after a layer of liquefied gelatin has formed, further liquefaction at 

 17 C. is very slow and does not take place at all along the line of 

 puncture. It often requires a month for the 10 c.c. of gelatin in the 

 test tube to be entirely liquefied. 



Potato. Growth abundant, moist, shining, slimy, raised and piled 

 up, forming a thick coating that in about two months becomes viscid, 

 finally filling up the fluid with a yellow, slimy growth. Color of the 

 growth on potato cylinders was at first white, changing in a few days 

 at 18 C. to sulphureous (Sacc. Chrom.), and in about six days to 

 a pale lemon yellow (W. and N.). At the end of a month the color fre- 

 quently became citron yellow (W. and N., plate No. 5). In cultures 

 two months old the color changed to raw umber shade (W. and N.) 



The growth on sterilized potato is very characteristic because of 

 the white fermentation band that appears just beyond the margin of 

 growth. This can be observed on potato cylinders, or better still on 

 slices of potato sterilized in petri dishes. The white zone usually is 

 visible within three days from inoculation when the organism is grow- 

 ing at a temperature of 20 C. to 26 C. In a few days the fermenta- 



