1896,] 
= 
Q 
The Bacterial Diseases of Plants: 913 
media is sterile to begin with and the necessary pre- 
cautions are taken to exclude surface contaminations 
and air-borne germs. His experiments were, however, 
checked and controlled by means of poured plates, 
whereas Dr. Wakker had advantage of no such exact 
method. Nevertheless, he seems to have worked with 
great care, and states positively that although the 
bacteria were often transferred from diseased plants 
to the culture media, and also from one tube of media 
to another, the results were always the same, which 
could scarcely have been the case were intruding or- 
ganisms present. 
Yes (?). Infections with artificial cultures had not 
been secured up to March, 1895, and do not appear to 
have ever been very numerous or very successful. 
The only experiment which seems to come properly 
under this head was begun March 4, 1886. The in- 
oculations were made from a liquefied gelatin culture, 
the fluid being inserted into fresh cuts on the scapes 
of several (more than five) varieties of hyacinths. 
In a week all of the scapes began to dry out and 
soften, from the summit downward; and fifteen days 
later the greater part of each one was either entirely 
dry, or soft and flacid. An earlier effort to infect from 
a bouillon culture failed (Verslag, 1884). 
(D) Yes; in part. On microscopic examination of the 
scapes mentioned under C it was easy to determine 
in them the existence of the yellow disease; but 
this did not extend into the bulbs. “ These experi- 
ments [referring to those mentioned under I (5) as 
well as this one] were repeated and varied with, in 
general, concordant results.” 
Cotvelivaion. —Pathogenic nature rendered probable. 
Remarks.—As will be seen later on, this organism was im- 
perfectly described, and any bacteriologist having opportunity 
to repeat and extend Dr. Wakker’s experiments should by all 
means embrace it. 
