798 The American Naturalist. [Oċtober, 
an abstract of the earlier Dutch papers. Part of the litho- 
graphic figures in the plate are, however, new. 
Remark.—The papers published by Dr. Wakker in 1883 and 
1884 were among the first contributions of any importance to 
the bacterial literature of plant diseases, but they were not, 
as claimed, actually the first. That honor belongs to this 
country, as we shall see later on when we come to take up 
pear blight, Prof. T. J. Burrill having published a long paper 
in 1880. The lack of literature and the difficulties in the way 
of the successful prosecution of this work at that time are well 
expressed in the Verslag for 1883: Als oorzaak van een 
plantenziekte waren Bacterién nog slechts eenmaal en dot 
wel zeer kort (Prillieux Bull. d.l. soc. bot. d. Fr. 1879, p. 31 
and 187) beschreven zoodat het geval van het geelziek niet 
alleen van praktisch, maar ook van hoog wetenschappelijk 
gewicht is. Is daarom het onderzoek er van zeker her belang- 
wekkendste van alle ziekten, waarmede wij ons hier zullen 
bezighouden, het is ook tevens het moeilijkste omdat bij gebrek 
aan mededeelingen omtrent dit of een dergelijk onderwerp 
alles op eigen onderzoek berusten moet. 
(2) Geographical Distribution—This disease has prevailed 
extensively at times in the large bulb gardens in the Nether- 
lands, where it is said by a majority of the Dutch horticultur- 
ists to be a new trouble, i. e., one that has appeared within the 
last ten years (31) or within the last 20 years (34). The 
writer of this digest has never been able to find the disease in 
bulbs imported from Holland, and does not remember to have 
seen any account of its occurrence in other parts of the world. 
(3) Symptoms.—According to Dr. Wakker the first symptoms 
of the disease are usually in the foliar and floral organs. 
There is an apical browning or blackening of the leaves and 
scapes which color can often be traced downward into the green 
leaves for some distance in the form of dark stripes. The epi- 
dermis frequently ruptures longitudinally, and large irregular 
masses of bacterial slime exude from the rifts. The diseased 
parts also have a wet, unctuous appearance, and shrivel from 
the apex downward. Subsequently the bulbs become dis- 
eased, and clearly as a result of the preceding disease of the 
Vat 
