1850. 470 
THE COTTAGE GARDENEH AND COUNTRY G 
con-oiled in the centre. Even in this early stage of growth, 
wlien the surface of the cuticle is still but little injured, 
and the disease confined to a discolouration of a few of the 
cells of which it is composed, oh the removal of the outer 
i coat little pale specks are visible on the smooth subjacent 
; surface, indicating precisely the situation of the incipient 
i pustules. In the course of a few days the spots spread, 
j become paler, and are abraded in the centre; and if the 
' cuticle is now torn off, it will be. found that where the spots 
! are situated it is protruded into the substance of the tuber, 
: the subjacent cells being at the same time absorbed, so that 
i the exposed st^-face of the tuber is covered with little pits 
I of a paler colour than the rest, and more transparent, and, 
I in red varieties, distinguished by the absence of colouring 
i matter. If a section be made through the pits, the cells 
J will be found to contain but little fecula, and their walls to 
change shortly to a reddish-brown. The cells of the base 
of the pustule still form a portion of the cuticle, which 
has, however, been more or less incrassated as the outer 
layers of its tissue were corroded. 
Fig. l. 
Fig. l. Vertical section of a young pustule, showing that the structure 
of the pustule is the same as that of the skin of the tuber. 
Fig. 2. 
Fig. 2. Vertical section of an old pustule, a. Skin of tuber; b. Cells 
immediately beneath the skin, containing colouring matter! c. Cells 
at the base of the pustule ; d. Starch cells. 
Fig. 3. 
Fig. 3. Vertical section of a cracked tuber tissue at base of a crack 
through the centre of a fissure. more highly magnified. 
The pustules now become confluent and deeply excavated, 
their inner surface being more or less scaly and corroded. 
As long as the cuticle is easily separable they separate with 
it, whether fresh or boiled, so that the tubers, when served 
at table, appear shining and smooth if the cuticle is nicely 
peeled, the diseased spots being indicated by scars re¬ 
sembling those left by the small-pox. The quality of the 
Potato itself is little altered, except that it acquires some¬ 
times a slightly earthy flavour, if, indeed, that is really at¬ 
tributable to the disease; and, according to the virulence of 
the disease, there is a slight difference in the quantity of 
•1 NT LEM AN’S COM PAN ION.— September SM, 
fecula contained in the tubers. In this stage of growth it is 
not uncommon to find some species of Poduridus revelling 
in the scurfy cavity of the pustules, and threads of a yellow- 
brown mycelium, which is probably that of liotrylis vulgaris 
or some nearly-allied species, traversing it, but not pene¬ 
trating far beneath the surface. These, however, are merely 
accidental and secondary phenomena in the malady. 
By the time that the cuticle of the tubers has become 
well fixed, the spots, which are still more rough and ex¬ 
cavated, often present a very unsightly appearance, but in 
every case, however complicated, a tissue very much re¬ 
sembling that of the cuticle is presented under the micro¬ 
scope; for, though the pustule has been excavated perhaps 
a line below the surface, and the original cuticle is seen 
surrounding the pustule, while the continuity between it 
and the cavity of the pustule which existed for some time 
after the appearance of the disease is quite dissolved, the 
whole of the diseased surface exhibits a muriform arrange¬ 
ment of the cells, those of all the strata of which it is com¬ 
posed being for the most part coterminous ; the individual 
cells are, however, far larger and coarser. The manner in 
which these cells originate is very obscure, whether from a 
modification of the more superficial cells beneath the cuticle 
or from a hypertrophy of those of the cuticle itself. I am 
inclined, however, to the latter view, though it is not with¬ 
out difficulty, and the analogous case of cracked Potatoes, 
which I was enabled to study, more partially indeed, at the 
same time, has made the matter at least doubtful. 
After the summer drought and the subsequent rains, a 
crop of very smooth-skinned Potatoes was much cracked 
from the inability of the tubers to accommodate the sudden 
increase of moisture. I was surprised to find, on examination, 
that these exhibited phases very similar to those of the 
scabby crop; the tissue beneath the cracks was transparent 
at first when cut, and nearly void of fecula, and became 
more rapidly rusty than the other parts of the tubers, and, 
what is of more importance, the disc of the fissures ex¬ 
hibited under the microscope the same muriform tissue, 
though here also the connection between that and the 
cuticle was dissolved. I had no opportunity of ascertaining 
the condition of the tissue when the fissures first took place, 
which would probably have show n at once of which of the 
two sets of cells, the cuticular or sub-cuticular, it was a mo¬ 
dification. In this instance I observed something which 
may perhaps indicate the mode in which the uniform tissue 
is formed. It will be seen in Fig. 4 that between two con¬ 
tiguous radiating series of cells a little wedge of cells has 
been interposed, of which the broad end consists of double, 
the narrower of single cells. This process repeated would 
clearly produce a tissue like that in question. 
In the case of cracking, the evil is evidently mechanical; 
and as the phases, as far as they have been observed, are so 
extremely like those of the disease we have been con¬ 
sidering, I am inclined to think that that is in great measure 
mechanical also. The first decay of the tissue, which is 
confined to a mere speck, is probably caused by contact with 
some irritating particle in the soil, and when this is estab¬ 
lished, the corrosion of minute insects and the exposure of 
the tissue to external agents, accompanied by a constant 
effort to repair the damage, may be sufficient to account for 
it, for the disease is absolutely confined to the surfnee, and 
never penetrates to such a depth as to cause any general 
disarrangement of the tissues. 
If sucli be a correct view of the case, which is submitted 
to further investigation, the remedy will consist in avoiding 
all such substances in the cultivation of Potatoes as are ob¬ 
served to be accompanied by scab. This will be best ascer¬ 
tained by the practical agriculturist, and would probably not 
be very difficult if care be taken not to confound the two 
very distinct diseases which pass under the common name 
of scab .—(Horticultural Society's Journal.) 
NOTES FROM PARIS. 
A geand Flower Show of three days’ duration was lately 
held in the spacious Orangery of Versailles, and I think, 
though I have been unable to send my notes sooner, that 
you will probably be the first to publish any -notice of it. I 
only saw it on the third day (the Dili of September); but 
