96 CROWN-GALL OF PLANTS. 



HARD GALL OF APPLE ON DAISY. 



Inoculations op February 24, 1908 (Smith). 



Six Paris daisy plants were inoculated with 4-day-old slant agar 

 cultures (from beef-bouillon culture of February 18, from stock agar 

 stab of Januar}" 6) of Doctor Hedgcock's first(D. C) apple gall. Each 

 plant was inocidated in two places in the top. 



Result. — June 1, 1908: No tumore. Plants discarded. Same cul- 

 tures were negative on apple of January 23, 1908. 



Inoculations of October 22, 1908 (Brown). 



Four daisy plants were inoculated on the upper part of the stem 

 from colonies on plates poured October 15. These colonies, how- 

 ever, had not appeared until October 20, so that the greater part of 

 the cultures were in reality only 2 days old. 



Result. — November 6, 1908: Small Ivnotty growths had formed on 

 all the daisies; not like the regular daisy gall in shape, but more like 

 that of the hard gall of apple. 



August 21, 1909: The galls have increased in size yqvj materially, 

 as shown by the photograph (PL XV, fig. 1). 



Inoculations of November 9, 1908 (Smith). 



Eight young Paris daisy plants were inoculated from cultures 

 plated November 4 out of a very hard gall of the apple, forwarded 

 by Doctor Hedgcock from Iowa. A 1 -millimeter loop was usually 

 scraped across a half dozen of the small colonies in order to get 

 enough material, and then tliis was rubbed on a small area on the 

 surface of the stem near the top of the plants and pricked in with a 

 sterile needle. What remained on the platinum loop was rubbed 

 over the wounds afterwards. As checks, the daisy plants were 

 punctured in another place with a sterile needle. For tliis purpose 

 plants were selected wliich had twin branches, one branch being 

 inoculated and the other check pricked. The gardener was directed 

 to withhold water for a few days until the check VNOunds should have 

 healed over, so that the organism might not be scattered from the 

 surface of the inoculated part into the priclvs on the other branch. 

 The plate used for these inoculations was photographed (PI. XXV, 

 fig. D). 



Isolation of organisms. — The details of making these poured plates, 

 their later appearance, etc., are as follows: 



Two plants onl}- of the hard gall were sent. The galls were found 

 to be verv hard indeed and not much raised above the surface of 

 the apple stem. The surface of one of the galls was washed and then 

 soaked for 3 minutes in 1 : 1 ,000 mercuric-chloride water. It was then. 



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