406 BACTERIAL DISEASES OF PLANTS 



through stomata, i.e., by spraying young actively growing shoots 

 under a bell jar. This should be tried repeatedly (in moist air). 

 Is there any special reason why stomatal infections would be 

 more than ordinarily difficult? Cut sections of the olive leaf 

 and study the stomata. Often, perhaps always, the disease 

 begins as a wound infection. 



Olives may be propagated from cuttings, but in most in- 

 stances it will be more convenient to buy the few plants needed 

 from some nurseryman who makes a business of growing them. 

 They should be young plants, and in the extreme southern part 

 of the United States, and similar climates, they may be grown 

 out of doors, but in most parts of the temperate zones they re- 

 quire a warm house. They should be planted in good earth, 

 but do not require large space. I grow them preferably in a 

 deep bed, but if more convenient they may be in small tubs or 

 large pots. Many varieties are subject to the disease. 



If cuttings are made they should be from side branches (ter- 

 minal 5 inches), not in new growth. These are bedded (lower 

 two-thirds) in sand and watered sparingly, the lower leaves 

 being cut away close and the upper ones trimmed back one-half 

 to two-thirds. Several months are required to root the cuttings 

 and they cannot be used the same year. 



Determine 



FOR THE ORGANISM. Morphology. Size in microns, us- 

 ing young cultures on various media. Search for chains, fila- 

 ments and pseudozoogloeae. For elongated forms examine 

 young cultures in bouillon, Cohn's solution, Uschinsky's solu- 

 tion (contrast with Bacterium mori), peptone water with 1 per 

 cent grape sugar, with 2 per cent glycerin, etc. Are capsules 

 formed? Petri says they are not. Try viscid potato cultures. 

 Search for spores. What are your reasons for thinking none are 

 formed? Examine for motility on the margin of a hanging 

 drop, using old and young cultures. Stain for flagella, deter- 

 mining the number and point of attachment. Select your own 

 stain. Is the organism acid-fast? Does it stain by Gram? 

 Are there any involution forms? Petri has figured interesting 



