107 
Thumen, Felix yon. Die Bekampfung der PiIzliranIsheiten nmerer 
Cullurgeicachse. Versuch einer Pflanzentherapie zuin praktisclien 
Gebrauclie fiir Land- und- Forstwirthe, Gartner, Obst- nnd Wein- 
ziicliter. Verlag von Georg Paul Faesy, Wien, 1886, paper, 8vo., 
pp. 157. 
This modest little volume is a move in the right direction, and de¬ 
serves more attention than it appears to have received in this country. 
In a brief and interesting manner, albeit not in very choice German, 
the author describes some of the more destructive fungous diseases of 
orchard, garden, field, and forest, and states concisely the best methods 
of dealing with this class of diseases. In reading, however, one is 
especially struck by the advance which has been made in the treatment 
of the vine mildew, Peronospora , since 1885, when the author wrote : “A 
favorable result is not to be expected from any fungicide; up to this 
time at least all proposed remedies have proved totally inadequate, or 
at least impracticable on a large scale.- 7 
Thirty five distinct diseases are included, distributed as follows: 13 
on field crops, 10 on fruit and garden vegetables, 6 on the vine, and 6 
on forest trees. 
In the introduction, which to the general reader is, perhaps, the most 
interesting portion, Professor von Thumen discusses those special con¬ 
ditions which, in his judgment, favor the increase of this class of dis¬ 
eases. They are: 
(1) The accidental introduction of foreign parasites ( Pinschleppung ). 
(2) The almost universal neglect of field hygiene, meaning by this the 
destruction of neighboring wild plants, etc., which might harbor injuri¬ 
ous fungi. 
(3) The growth of one crop repeatedly ( Hypercultur ) whereby every 
opportunity is given for the excessive multiplication of parasites. 
(4) Propagation by unnatural methods, i. e., by layering, budding, 
grafting, etc. 
(5) The ever-increasing business intercourse and movement of popu¬ 
lation. 
It is apparent from these statements that the author believes the 
control of this class of diseases lies largely in the hands of the cultivator. 
He should guard against foreign enemies; he should carefully destroy 
weeds, etc,, likely to harbor parasitic fungi; he should practice rotation 
of crops ; he should return as much as possible to varieties raised from 
seed, and, finally, he should keep a sharp watch lest enemies be intro¬ 
duced from neighboring localities in unsuspected ways, e. g., with goods, 
seeds, grains, vines, etc. 
His remarks on “the root-mould of the grape-vine 77 appear of suffi¬ 
cient interest to be reproduced in full, especially in view of the possi¬ 
bility that the mysterious and destructive vine disease of California may 
be due to some similar parasite. 
u Within a few years—about six or eight—numerous complaints have 
