362 
THE COTTAGE GARDENER. 
[September 12. 
A scientific correspondent (a physician residing in 
Norfolk) writes to us as follows:— 
“ I think I mentioned that my potatoes were perfectly 
sound. I had about eight rods of the Ash leaved kind, 
which we took up as we wanted them for the table. The 
tops of the remainder, about six rods, having died off, I had 
them taken up, and I am sorry to say the greater part of them 
are diseased. The outer skin in brown patches, and when cut 
into, it extends in some from one-sixth of an inch to the 
middle of the potato. This disease must have come very 
suddenly and quickly, as I examined them daily in different 
parts of the bed and none were found touched with it. The 
crop is very great, there being rather more than a sack to 
the rod. In the same piece of ground I have a large space 
with the Cambridge Red Kidney, and a round white potato, 
the name of which I know not. In the stalks of many I find 
brown patches, as if they were naturally dying off, and upon 
examining the tubers they appear perfectly sound, and seem¬ 
ingly full grown, but the skin easily abraded by the finger. 
I have had the tops mown off close to the ground. I wish to 
ask you, under the present state of the tubers (which I am 
told are hardly fit to be taken up, and if taken up they 
will not keep), what is to be done ? The disease may attack 
them as the others, and to let them remain until the middle 
of next month—when I took them up last year—I fear the 
loss may be greater: what would you advise me to do ? This 
disease appears to baffle every one, and until we know its 
real nature, we shall remain unable to prevent it. The first 
thing to understand is the construction of the plant and cir¬ 
culation of the sap, and a chemical examination of a diseased 
stalk, and also a healthy one; the result may lead to some 
conclusions, whether or not the disease takes its origin from 
atmospheric causes or from the soil. It seems singular that 
it should occur yearly; this is not the law of epidemic 
diseases ; and the same law exists in the vegetable tribe as 
in the animal. For those potatoes I now have cut off, the land 
was well limed when set, and to this I attributed tlie escape 
last year, when my neighbours did not. From your ex¬ 
perience as a practical gardener you can inform me, whether 
lime has a beneficial effect on the present occasion. In ex¬ 
amining the principal root of a diseased tuber, I find it brown 
and pulpy, while that of a healthy one is white and some¬ 
what finer. This has induced me to think the soil has some¬ 
thing deleterious to the plant; but why should it not 
attack all the tubers of the same plant ? so that it is a 
most puzzling complaint. Has the degeneration of the 
plant any influence ? And do we not require a new stock ? 
However, I could fill sheets by inquiries; and shall shake 
your patience and waste your time ; I shall, therefore, con¬ 
clude by requesting at your leisure your observations and 
advice.” 
Immediately upon the receipt of this letter we wrote 
to our correspondent, and recommended him to take up 
all his potatoes, and store them as fully directed in our 
last number. By leaving them in the ground they are 
more liable to the access of moisture, and to occasional 
high temperature, than they are when stored between 
layers of earth, &c., under cover. 
It so happened that immediately previously to the 
receipt of our correspondent’s letter, we had been 
reading Mr. Cuthill’s very excellent pamphlet, Practical 
Instructions for the Cultivation of the Potato, j ust pub¬ 
lished, and some comments wo have to offer upon it will 
serve to answer our correspondent's inquiries. 
Mr. Cuthill commences by observing :— 
“ It seems to be agreed that we must look upon atmo¬ 
spheric influences, of the nature of which we are able to give 
no account, as largely concerned in the production of the 
evil; yet, as I believe I can show in the following pages, im¬ 
proper modes of cultivation have greatly aggravated, if they 
did not even give the first occasion to, the destructive 
visitation which has fallen upon the plant." 
Now, how much we agree with this will appear from 
the following extract from a pamphlet we published in 
1846, entitled The Potato Murrain and its Remedy :— 
“ It has been suggested that either fungi or insects are 
the cause of the disease; but I think both these are ex¬ 
cluded by the fact that it appears in every quarter and 
latitude of the globe,—in the frigid climate of North America, 
in the temperate locality of Devonshire, and between the 
tropics at St. Helena. Now, I know of no fungus or insect 
that has it habitat alike uninfluenced by heat or cold; and 
even less conceivable is it that a fungus or insect is just 
created for the purpose of destroying the potato crop. The 
fungus or insect, it is more rational to conclude, must have 
existed throughout time, and its ravages have only been felt 
by increasing degrees, as the potato has gradually reached a 
state of disease fitted for the nutriment of the parasite. The 
same and other facts preclude unfavourable seasons from 
being the cause of the disease, though they may hasten its 
progress. Tlie disease is said to be as prevalent this year 
(1840) as last, yet no two years could have had seasons more 
different. It is quite clear that no local cause—such as the 
employment of any particular manure, the staple of the soil, 
or the mode of culture—can be the origin of the disease, for 
the crop has been grown on all possible varieties of arable 
soil, with and without manures, and in various modes ; the 
sets have been dug in, and dibbled in,—the plants have been 
earthed up and left unearthed,—yet in all and in each has 
the disease appeared. The cause, then, must be one of 
universal applicability, for the disease is epidemic in tlie 
widest sense of the term. Does it arise from the vital 
powers of the varieties being exhausted ? No; for, in many 
instances, the most recently raised from seed are as pro¬ 
ductive of diseased tubers as the oldest cultivated lands. Does 
it arise from the almost universal practice of taking up the 
tubers as soon as the stems are dying or dead, and keeping 
those tubers out of the soil for four, five, or more months ? 
I am of opinion that this is the cause.- The practice is nearly 
universal; it is the practice throughout Europe, as it is in 
America, St. Helena, and the hill districts of Hindustan ; 
and in all those regions the disease prevails. It is not the 
practice in New Zealand, and there the disease is unknown. 
Now, has the withdrawal of bulbs and tubers from the soil 
tlie effect of gradually rendering them and their progeny 
diseased ? I think no horticulturist or vegetable physiologist 
will answer in the negative. A writer in the Gardener's 
Chronicle of the present year (p. 478), most correctly observes, 
that the bulbs of hyacinths, tulips, and crocuses, keep well 
in the ground, but, if taken up, have a strong tendency to 
decay. Rut what effect has this treatment upon the plants 
to which they give birth ? Why, it imparts to them disease. 
The strain, tlie beauteous variegation of the tulip’s petals, 
are the effects of disease. Leave the bulb in the soil through¬ 
out the year, and it returns to its natural vigour and simple 
colours. No variety occasioned and preserved by such arti¬ 
ficial treatment will endure a few years. It is no effectual 
objection that seedling potatoes are now affected with the 
same disease, for such diseases are hereditary in vegetables 
as well as animals, and the seedling’s tubers have been sub¬ 
jected to tlie same keeping out of the soil for months as 
were its parents. Neither is it an effectual objection to say 
that only recently the disease has prevailed, for it has been 
noticed for full fifteen years, and it is only by such detention 
from the soil through a series of years [that the disease is 
advanced to its prevailing malignant form.” 
Mr. Cuthill then proceeds to detail his mode of culture, 
and this requires no other statement than this, “ during 
ten years my crops have never been attacked by the 
disease,” to command from every cultivator the most 
serious attention. An epitome of his practice is this : 
thinking that the potato ought to have a change of soil, 
he buys his sets in October, before they have sjirouted; 
greens them in the sun; and stores them and keeps 
them quite dry, “ with their heads all one way, to pre¬ 
serve order at taking up time when planted out,” under 
a stage in a cool greenhouse. About the middle of 
January, when they have shoots an inch long, they are 
