142 CROWN-GALL OF PLANTS. 



(2) Fluid feebh" clouded, some strings and flocks, pellicle incom- 

 plete, thin, fragmenting, not much precipitate: Salsify, parsnip, 

 arbutus, grape, apple hairy-root, new apple, Newport poplar No. 1. 



(3) Thin cloudy, no rim, no pellicle, but a precipitate which makes 

 the fluid cloudy on shaking: Beet. 



(4) Trace of rim, no pellicle, no strings, moderate clouding, slight 

 precipitate: Willow. 



(5) Moderately cloudy, trace of rim, no pellicle, quite cloudy on 

 shaking, but not much flocculence, and no strings: New chestnut. 



(5a) Moderate white rim and very scanty pellicle, quite cloudy with 

 much coarse flocculence on shaking, but no strings: Newport poplar 

 No. 2. 



(6) Fluid clear, no rim, no pelhcle, no strings, or filaments; thinly 

 clouded on shaking by a great number of fine pseudozoogloese: Old 

 apple. 



(7) Like 6, but clouds on shaking with a finer precipitate: Quince. 

 At the end of a month the tubes still fell into the old groups and 



none of the fluids were brown stained. When tested with neutral 

 litmus paper the cultures gave the following reactions: 



Group 1. — All strongly alkaline except alfalfa (slightly alkaline) and newest 



daisy (neutral or slightly acid). 

 Group 2. — Much less growth: New apple (slightly acid); apple hairy-root and 



arbutus (neutral) ; grape (alkaline) ; Newportpoplar No. 1 (alkaline); parsnip 



(alkaline); salsify (neutral). 

 Group 3. — Beet (strongly alkaline). 

 Group 4- — Willow (strongly alkaline). 

 Group 5. — New chestnut (slightly alkaline). 

 Group 5a. — Newport poplar No. 2 (strongly alkaline). 

 Group 6. — Old apple (2 tubes, plainly acid). 

 Group 7. — Quince (2 tubes, alkaline). 



Only groups 1 and 2 contained organisms of recently proved 

 virulence. Subsequently the willow was proved to be pathogenic to 

 willow. 



MALTOSE PEPTONE WATER. 



When grown for 3 months in river water containing 2 per cent 

 Witte's peptone and 1 per cent maltose the strains behaved as 

 follows : 



(1) Fluid clear, unstamed, slight stringy rim, moderate flocculent 

 precipitate which clouds fluid on shaking: Newest daisy (neutral to 

 litmus), alfalfa (strongly alkaline), arbutus (acid to litmus), apple 

 hairy -root (strongly alkaline). 



(2) Like 1, but fluid brownish and alkaline: Grape. 



(3) Clear unstahied fluid strongly alkaline to litmus, pellicle 

 0.5 cm. thick, slight precipitate: New rose. 



213 



