149 



on unplugging its odor was alwa^^s perceptible in the mouth of the 

 tube. 



The chloroform exerted a marked retarding influence on Ps. hya- 

 cinthi^ but did not always prevent its growth. The tube was first 

 inoculated with two 3 mm. loops from a 10-days-old moderately 

 cloudy culture in Diuiham's solution. In 24 days (at "KP to 25"^ C.) 

 there was no growth. The tube was now reinoculated with two 3 

 mm. loops of cloudy broth from a 3 -days-old culture in stock 382. 

 After 12 days there was a faint surface clouding and a feeble partial 

 rim of germs, which indicated that growth was proceeding with much 

 difficult}'. A month later there was a good, dense, yellow rim, 2 nnu. 

 wide, the fluid was well clouded, and on top of the chloroform there 

 was a loose yellow bacterial precipitate about 2 mm. deep. 



For comparison with P.s. hyacinth I tubes of the same medium were 

 inoculated with other organisms. Under the same conditions Ps.. 

 camj)estris refused to gro^^'. The tube was first inoculated with two 

 3 mm. loops from a 10-days-old moderately cloud}' culture in Dun- 

 ham's solution. After 24 days, there being- no growth, the broth was 

 reinoculated with two 3 mm. loops from a well-clouded 3-da3's-old 

 culture in stock 382. After 43 days, there being no growth, the tube 

 was inoculated for the third time with a 2 mm. loop of solid slime 

 from a 48-hour growth on the surface of cooked turnip. This slime 

 was broken up in the fluid by means of the platinum loop, and after- 

 wards divided to a still greater extent bv shaking the fluid thoroughly. 

 The tube was under observation for an additional 13 days, but no 

 growth ensued. 



Ps. stewarti., on the contrary, grew in this chloroformed beef broth 

 abundantly, with only slight retardation, and remained alive in it for 

 more than 2 months. The tube was inoculated with one loop from a 

 10-days-old culture in Uschinsky's solution. 



A number of other organisms behaved in much the same way as 

 Ps. stevmrti^ i. e., the\' were more or less retarded for a few da3's, 

 but afterwards made a more or less copious growth. Among these 

 were B. amylovorvs., B. carotovomis., B. j^yocyaneus lyericarditidis., 

 and B. coli. Ps. jj/uiseoh' grew slowly in chloroformed cane sugar 

 bouillon Avhen inoculated copiously. 



MEANS OF DISTINGUISHING THE FOUR SPECIES OF PSEUDOMONAS. 



The four species of Pseudomonas may l)e distinguished as follows: 



1. Cruciferous plants — cabbage, cauliflower, kohlrabi, kale, rape, 

 turnips. rutal)agas, ninstanls. I's. I'ajiijH'ntris. 



2. Legiuuinuus plants — Ijeans vi various kinds, e. g., lima beans, 

 Found in , { bush beans. Ps. phaseoU. 



3. Liliaceous plants — hyacinths. Ps. hyacinthi. 



4. Gramineous jilants — maize, especially sweet corn. Ps. 

 steinu-ti. 



