1896.] The Bacterial Diseases of Plants : 729 
(2) Natural Methods of Infection.—Not determined. 
(3) Conditions Favoring the Spread of the Disease—Not deter- 
mined. 
(4) Methods of Prevention—No experiments recorded, and 
nothing known. 
Remark.—F rom the statement quoted under Pathogenesis (C) 
one might infer this to be a preliminary paper, and it is possible 
that a subsequent one may clear up some of the many mooted 
points. At present the most that seems to be made out beyond 
doubt is that there is in Indiana a disease of sugar beets accom- 
panied by decreased sugar content, and always or usually associ- 
ated with minute bodies distributed pretty uniformly through 
the parenchymatic tissues, and believed to be bacteria. To the 
writer of this article the evidence that bacteria are really the 
cause of this disease does not appear to be very conclusive. 
Until more proof is advanced it is permissible to doubt (1) 
whether the organism isolated by plate cultures, and supposed 
to have been derived from the interior of the beets, was actually 
so derived; and (2) whether the bacteria-like bodies which 
“occur in great numbers in every cell of the plant,” but which 
“never break down the tissues,” or cause “any alteration or 
discoloration of the tissues,” are really micro-organisms. To 
have every cell full of aerobic bacteria, and no lesions, is very 
remarkable, considering the nature of the plant cell, and cer- 
tainly requires unusually strong evidence. Under the cir- 
cumstances is it not possible that these bodies may be of a 
crystalline or crystalloid nature? This seems the more likely, 
from the fact that the juice of healthy table beets, the only sort 
the writer has been able to examine, is full of small particles 
endowed with active Brownian movement, and readily mis- 
taken for bacteria when examined in hanging drops with me- 
dium magnifications. The uninjured parenchyma cells of the 
petioles were also found to contain these bodies in large num- 
bers and in active motion. They stain slowly with alkaline 
methyl blue, and are not microérganisms. 
4. THE DEEP SCAB OF BEETS (1891). 
In (27) Bulletin No. 4, Agric. Experiment Station, North 
Dakota, Fargo, N. D., Dec., 1891 (pp. 15-17), Prof. H. L. Bolley, 
51 
