THE MULBERRY BLIGHT: CAUSE 



349 



on 4th day; best growth in top on 6th day when it was bluish- 

 fluorescent; many pseudozoogloeae; no distinct pelhcle; after 6 

 weeks, greenish-fluorescent, very copious white precipitate and 

 still heavily clouded (contrast with XIII); organism motile; no 

 filaments observed. 



In peptone water in fermentation tubes no clouding of the 

 closed end with dextrose, saccharose, lactose, maltose, glycerin 

 or mannit. Contrast with No. I. 



Indol production is absent or feeble. Compare with No. VI, 



^f^^^^J 



m 





-r 



^z^^i'-'' 



Fig. 269. — Bacteria of mulberry blight: a. Bacterial cavity in bark of the 

 young mulberry shoot shown in Fig. 268; most of the bacteria were washed away 

 in making the preparation. Remnants of tissue on the periphery. Over-stained. 

 X 1000. 



b. Center of small cavity in bark of a mulberry shoot inoculated on grounds 

 of the U. S. Department of Agriculture in 1910. X 800 circa. 



Grows from 1°C. to 35°C. but remains alive in bouillon for 

 only a short time at the latter temperature. Thermal death- 

 point about 51.5°C. 



Grew twice in +15 peptone bouillon containing 7 per cent 

 sodium chlorid but would not tolerate 9 per cent. (Compare wdth 

 No. VI and contrast with No. I.) 



Pseudozoogloeae and involution forms occur. 



On thin-sown agar plates all bacteria on the exposed side 

 were killed by 36 minutes exposure to sunlight, bottom up on 

 ice; 26 minutes killed nearly all. 



