Milford chronicle., 1889-07-19
The Agricultural Experiment Sta
ton.
BOTANY AND BAcrERIoLoGY.

practical use to the farmers and orchardist
IT of Delaware, by means of the department o
u Botany and Bacteriology.
r The botanical laboratory is thoroughly
e equipped for the best work in the depart
u ments Of this science.
n The microscopic outfit is especially good
j. and includes number of plain instruments
q for ordinary work; and No. Zeiss stand,
l.. with a complete set of his highest series OF
9 oil and water immersion detectives. With
this outfit, the department is provided with
every accessory for astrological work. Be-
sides the ordinary accessories such as dis
! secting microscopes, dissecting instruments,
micro-reagents,- turn tables, microscopic
lamps, condensors and camera lucidas, a
I Thoma microtome from Jung in Heidelberg,
} and "a Reeves water-bath may be especially
! mentioned.
The relation ofmicroscopic work, for which
this equipment is intended, to the general
purposes Of an experiment station, is mani
fold.
The study of adulterated products, some
times sold to farmers, demands not only the
higher powers of the microscope, but also
requires the resources of micro-chemistry
As an illustration may be mentioned the fire.
queut adulteration of seeds, insect powders
drugs and food products.
But the most important use to which this
microscopic outfit is to be put is in the study
of diseased plant tissues. Most plant tissues
are Opaque. or at least so much so that the
microscope reveals but little of their struc-
Before this instrument can be used effect
lively, plant tissues must be cut in exceed |
| ingly thin slices, running in one direction or
another, so as to be rendered transparent. !
By means Of the Thoma-microtome above |
mentioned, it is an easy task to cut an inde6- |
mite series of sections, through the same
organ, each as thin as the one two thous-
andth or the one three thousandth of an
inch, rendering them thereby highly trans
parent.
The section once cut, it must be stained
or otherwise treated with the various micro
reagents that the different structural ele-
ments in the section may be brought out
more clearly; it is then ready to be mounted
upon glass slide in some favorable medium
for permanent keeping. By such processes
as these, we learn, for instance, that a GER
tain plant disease, as grape mildew, is caused
by fungus growth, which sends its ex-
tremely delicate negotiating threads through
the structure of the leaf causing thereby a
disorganization and discoloration of the cell
contents which shows itself externally in {
deadening and crumpling of the foliage.
But the microscope reveals still more; it {
shows that these negotiating threads send /
out processes which pierce through the many /
breathing pores, or stomata, on the lower +
side of the leaf and become thread-like d
stalks of such characteristic form that a
botanlst at once recognizes them. Again it {
is shown that these stalks bear equally char II
oval bodies known as Spores In v
troduce into a drop of water few of these r
spores and watch them closely; before long "
they begin to send out thread-like processes;
in other words they begin to terminate like b
seedsr in fact they are seeds of the fungus b
causing grape mildew. Let a few of the Il
spores fall upon damp grape Leaf, and they II
terminate in the same way, and some time Il
after, the leaf shows signs of mildew These 81
experiments teach that the spores carry the il
disease from leaf to leaf. d
While the grape mildew has been taken p
as single instance, the same methods of W
study will apply to a hundred other plant m
diseases, and in all cases the microscope is the N
instrument which must give an insight into til
he nature ofthese maladies. al
Agoin, while it may be of interest to read b,
/ written description of the characters of the &C
ungus causing particular plant disease, the pc
interest would be greater could the reader 81
ook through the microscope himself; but b,
where the station has to communicate with
IS readers from distance, this is imposs- &c
lie. Fortunately, however, it is possible to as
tx upon a sensitized plate, the very image W,
which is impressed upon the eye Of the OBJ ST.
erver This plate can then, by the ordinary re
rocesses of photography, be converted into sp
picture, which picture can again be repro tn
uced as a bulletin illustration. The impor- fol
lnce Of photography in just representa- in
on of form and detail, cannot be over-esti- or
iated with this in view, the station has of
rovided itself with Photographic outfit of wi
he best quality. 1t includes a large and ON
NO small cameras for photographing large wi
bjects, and acknowledgement camera for str
lie work already alluded to. pa
The botanical laboratory is provided with an
good reference library, and all of the stand air
I'd English and German botanical journals of
The herbarium is especially enriched by a suC
,mplete set of two thousand one hundred Da
,ecies of Ellis's North American Fungi. dai
in complete manner the sub ma
ct of plant pathology. the
The department is at present arranging to
-epare a collection of useful and noxious
eds, to assist in the work of seed-testine, to
hich especial attention will be given. To \
is will be added collection of materials Dar
ed in the adulteration Of products con- A.,
med by the farmers, and Of such pure I'M mp
samples as will enable It to ma ke sew
ady comparisons. or
The archaeological laboratory, adjoining VIII
e general laboratory, IS provided with a =.
mplete set of Koch's apparatus, imported wat
I'm Berlin, including steam, hot air and nos
bod serum sterilizers, culture ovens, etc. ulcs
With these facilities it will be possible to ssh
dertake studies Of micro-orPani so far
they have direct practical bearing upon my
leases Of plants or animals, or upon fer trea
.ntations or putrefactive changes in the few
!. To this may be added a study of the -.
alton Of heterogeneous to changes af- iee'
ting folders, feeds and other products Of seVe
. farmer. any