344 



BACTERIA IN RELATION TO PLANT DISEASES. 



THE PARASITE. 



Bacterium hyacinthi* Wakker is readily isolated. In the plant and on agar and in beef- 

 broth, etc., it is a short rod, single or in pairs, or more rarely in fours joined end to end 

 (figs. 139, 140). Rarely short chains have been observed, e. g., on agar. It measures under 

 these circumstances 0.4 to 0.6 /xXo.8 to 2 /jl, but like many other organisms, it is longer or 

 shorter, thicker or thinner, according to age, culture-medium, and kind of stain used. It is gen- 

 erally slenderer than Bad. campestre or Bad. phaseoli. The following are some measurements : 



(i) February 5, i8p8. Slime from a daughter-bulb 

 stained 5 minutes in a saturated solution of basic fuchsin 

 (very weak stain). Rods short, 0.5 to i.o X0.4 to 0.5/i. 

 Two minutes in saturated watery solution of Gentian violet 

 gave a deeper stain but not deep enough. 



(2) February/, 1898. Alkaline beef -broth. No. i, Jan- 

 uary 29, 1898, stained 10 minutes in saturated watery 

 solution of basic fuchsin. 



2.0X0.4^1'! 



1 . 4 X o . 4m [single rods. 



I ,oXo.4mJ 



3. 6X0. 4m two rods joined end to end. 



3. 2X0. 4m two rods joined end to end. 



Widest rods seen o.6m. 



(3) July 31, i8g8. Slide of March 10 from very dilute 

 beef -broth 3 days old, Moore's flagella stain. Size i to 2X 

 0.5 to 0.7 ^JL. Flagella 3 times length of rods. 



(4) August 3, i8g8. Slide of March 17, 1897, agar stock 

 207, Fischer's flagella stain : 



2X0.8M 

 2 X I . om 



2 to 3X1 .Cm. 



2.5X0.8 to i .Cm several. 



(5) August 3, i8g8. Slide of June 23, 1897, made from 

 the interior of a bulb (yellow slime). Plant inoculated on 

 leaf February 16, 1897. Stain, basic fuchsin in water. 



i.oXosm two; 1. 5X0. 5m; 1.2X0. 5m; 

 Extremes, 0.9 to i. 5X0. 5m. 



Most I to 1 .2X0. 5m; 



Pseudozoogloeae are common. No spores have 

 been discovered by the writer, and the spores described 

 by Wakker probably belonged to some other organ- 

 ism, f This is the more likely because the cultures in 

 which they developed abundantly were made directly 

 from the bulb, i. e., not from colonies, and were kept 

 at a temperature slightly above the maximum for the 

 growth of this organism, as determined by the writer. 

 Making cultures from bulb scales in the same way as 

 Dr. Wakker, the writer has twice obtained mixed 

 growths from what looked like an unmixed source ; the yellow organism being contaminated 

 once by a green fluorescent organism and once by a white, gas-forming species. In the 

 plant and in the common culture media chains and filaments do not occur, or are rare, but 

 old cultures on media rich in sugar, e. g., streaks on dextrose-agar or saccharose-agar, often 



Fig. 137, 



*Synonyms: Bacillus hyacinthi (Wakker) Trevisan; Pseudomonas hyacinthi (Wakker) EPS. 



fThe endospores observed by Wakker were blue-shining, strongly refractive bodies, germinating equatorially. 

 They were cylindric with rounded ends, measuring im in length and being about one-half or two- thirds as thick. 

 They sometimes appeared at temperatures lower than 35° C, but less abundantly. 



{Fig. 137. — Cross-section of a hyacinth-leaf showing xylem part of the bundle occupied by a bacterial cavity, 

 parenchyma to either side being unoccupied. Leaf inoculated at apex in 1898 with a culture of Bact. hyacinthi. To 

 either side of the bundle are (C C) natural passage-ways through leaf. Slide 502 B-A7. 



