344 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



Spores. No spores from this organism have thus far been demon- 

 strated. Old cultures have many times been studied and special stains 

 used. Hauser 's method was used, but did not show anything suggestive 

 of spores. 



Capsule. The organism has never showed a true capsule, although 

 its viscid growth might suggest one, and a microscopic examination of 

 this viscid growth from potato cylinders and other culture media often 

 shows a very distinct and rather thick wall, that can easily be seen by 

 using some of the special stains recommended for capsules. This may 

 appear as a hyaline membrane from one fourth to one half as thick as 

 the remaining width of the organism. The following capsule stains were 

 used: Robberts' dahlia, Welch's and Bonis'. 



FIG. 87. 1, the walnut blight organism, Pseudomonas 

 juglandis, greatly enlarged ; 2, a mass of the bacteria 

 in diseased walnut tissue. 



Flagella. The organism is motile by means of a long, single polar 

 flagellum, as may be demonstrated by using BowhilPs method. The 

 movement of the organism is a slow, sinuous one in the direction of the 

 longer axis. 



CULTURAL CHARACTERISTICS. 



The culture media were carefully prepared, following directions as 

 given by Smith 1 and Moore. 2 The formula for preparing nutrient 

 bouillon was Witte's peptone 10 grams; (c.p.) sodium chloride 5 grams; 

 500 grams of finely minced beef to 1,000 c.c. of once-distilled water. In 

 making this the directions given by Moore were followed. 



1 Bacteria in Relation to Plant Diseases. 



laboratory Directions for Beginners in Bacteriology. 



