in this way — a very easy process, requiring no cutting, except enough 

 to start the peeling— the diseased spots could be as readily detected as 

 before. From one to twenty spots, varying in size from 0.5 to 2 mm. 

 in diameter, were inck^ded in each culture. The cells were broken up 

 as much as possible in scraping them out of the tissues, but great care 

 was taken not to allow the internal tissues to become contaminated in 



any way. 



burino- the first season's work about five hundred cultures were 



Fig. 3.— Cross section through the middle of a fully developed spot on a mature carnation leaf. All 

 the epidermal cells in the spot have collapsed. Most of the enlarged diseased cells have lost their 

 chloroplasts, and many of them contain globular vacuolate masses, M'hich arc portions of the dis- 

 organizing cell structure. (Drawn with Zeiss camera lucida, x 135 diameters.) 



made, various media being used— for instance, slightly acid, neutral, 

 and slightly alkaline beef broth, with and without peptone; potato 

 broth of various strengths; cauliflower broth; potato cylinders; agars 

 of various composition; gelatin (acid, neutral, and alkaline to litmus 

 and to phenolphthalein), etc. These cultures included many poured 

 plates made direct from the crushed tissues. In no case, however, 

 were orsanisms found in anv cultures made from a spot before the 

 epidermal tissues had collapsed. 



In preparing the material for the cultures, only that known to 



