378 THE COTTAGE GARDENER. February 13. 
Academy, form a very agreeable and nutritions article of 
food, and may be cooked in several ways, both boiled and 
roasted. 
About five years ago, a particular species was sent from 
China, by M. de Montigny, French Consul at Shanghai, 
and M. Decaisne has now given an account of the experi¬ 
ments, which he has for some time been directing, to test 
its hardiness and its nutritive value. He thinks this species 
differs sufficiently from Dioscorea Japonica to merit a distinct 
name, and he has given it that of Battutas. 
The tubercles of Dioscorea Battutas are always perfectly 
simple, without any branching, and they strike into the 
ground in a perpendicular direction. They are, on an 
average, about the thickness of one’s wrist, and their 
length varies between thirty and thirty-five centimetres 
(fifteen to eighteen inches). The weight of those at the 
Garden of Plants here has been, in general, about 300 
grammes (a little over ten ounces); sometimes, however, 
nearly 600 grammes. Their substance is white, tender, and 
mealy. In respect to their chemical properties, these 
tubercles much resemble Potatoes, though it lias been 
ascertained they only contain 16 per cent, of amidon, while 
Potatoes contain 30 per cent. The tubercles of the Dins- 
corea Battutas contain, on the other hand, an azote principle, 
a sort of gluten, which adds a little to its value as an article 
of food, and which is not found in the Potatoes. This 
azote, however, is only about 2 per cent. Resides entering 
with facility into every kind of culinary preparation, they 
also produce starch like Potatoes. 
The plants which were grown under the direction of M. 
Decaisne were planted near the end of April, and finished 
their growth by the middle of October; but in a warmer 
latitude than that of Paris, they might be expected t.o grow 
much more rapidly. It lias been ascertained that the roots 
will keep in the ground during winter, and they have even 
been uninjured in a temperature of twelve or fourteen 
degrees of frost. 
The tubercles of the Dioscorea may be stored and pre¬ 
served as readily as Potatoes, and they are not apt to 
sprout like the latter when placed in cellars. They are 
propagated with equal facility. 
Such are the recommendations of this novelty. Unfor¬ 
tunately, it has one drawback, which may prove an obstacle 
to its general introduction, and that is, the great length of 
the tubercles, which makes it somewhat difficult to get 
them out of the ground. The Chinese, who have cultivated 
this plant from time immemorial, usually grow it on ridges 
twelve or eighteen inches high, and this practice, in a great 
measure, removes the objection just noticed, for when thus 
treated, the difficulty of extraction is so far overcome. 
But it is only in field culture that this objection can have 
any force. 
When grown on a more limited scale, as in gardens, the 
lifting of the tubers is attended with but little inconvenience, 
and, probably, a mode of treatment suited to the circum¬ 
stances may be adopted, which will enable us to introduce 
it extensively in farms. The average length of the tubers, 
or rhizomes, is about eighteen inches, and they are always 
thickest at the lower extremity. It is t his peculiarity which 
will make them difficult to take out of the ground when 
grown largely as field produce, but, on the other hand, 
their length is attended with one real advantage, for a great 
number may be grown in a small space, and a large mass 
of nutritious substance may be thus produced. 
It has been calculated by Prof. Decaisne, that twenty 
plants may bo grown to the yard square, and that the pro¬ 
duce thus obtained is more than double that of Potatoes 
grown on a similar extent of ground. It is, however, pre¬ 
mature to give a full estimate of the value of this plant. 
Other and more extensive experiments, both in growing 
and cooking the tubers, will, doubtless, lead to a modification 
of the opinions which may be now entertained respecting 
them. Enough, however, has been done, to show that 
with careful cultivation, these “Potatoes of China” will 
deserve a place in our kitchen-gardens. The Dioscoreas 
belong to the order of that name, and are all twining 
shrubs, with tubers or rhizomes, and heart-shaped leaves. 
Dioscorea discolor is a beautifully variegated stove species, 
which may be taken as an excellent example in respect to 
the general habit of the gonus. Most of the species pro¬ 
duce what are known under the name of Yams, which are 
their large, fleshy, farinaceous tubers. In tropical countries 
these Yams are much esteemed as an article of food, being 
to the natives what I’otatoes are to the inhabitants of more 
temperate climates. The flowers are for the most part 
small and insignificant, but the foliage and general habit 
of the plants make them very ornamental for conserva¬ 
tories, where they should be trained to pillars, or on trellis 
work. 
At the same Meeting of the Acadcmie, the Secretary read 
a letter from the Minister at War, containing a notice of a 
novel application for the prevention of the Vine disease. 
The principal passage is worth quoting. 
“ Among a great number of recipes which have been 
brought into notice, and which experience has shown to be 
useless, one only appears to have answered the purpose, 
and that consists simply of dusting wood ashes on the 
leaves of the Vines. M. Vial, of Cheragas (a Department 
of Algeria), has the credit of introducing this new mode of 
treatment, the beneficial effects of which were tested during 
the last season on several crops in different soils and situa¬ 
tions. The discovery of M. Vial is very likely to be of ad¬ 
vantage to the Vine-growers of France, and, I believe, the 
notice of it will be interesting to the Academy. I, there¬ 
fore, beg you will have the kindness to place before the 
members the accompanying report, which I have received 
from the Prefect of the Department alluded to. In calling 
my attention to the experiments of M. Vial, and which he 
has had an opportunity of verifying for himself, that 
functionary has forwarded me several certificates from dif¬ 
ferent colonists who have made use of the new remedy. 
One of these documents is from M. Borely - Lasopie, 
Mayor of Boufarick, one of the chief Vine-growers of the 
country.” 
These documents have not yet been published, but the 
testimony of the persons mentioned is entitled to respect, 
and it is now for Vine-growers to try whether an application 
of wood-ashes is more effectual than sulphur as a remedy, 
or less objectionable as an application, with respect to the 
flavour of the fruit. 
A recent number of the Estafette contains a communica¬ 
tion signed “ M. J. B. Thomas,” on the planting and general 
management of trees. The directions given are worth notice, 
as being those of an arboriculturist in a country where 
agriculture, and everything relating to it, is under the 
encouragement and control of the Government. 
M. Thomas appears to have been induced to publish his 
views by the recent exploits of Mr. McGlashen, of Edin¬ 
burgh, in this quarter, and of which he takes a passing 
notice. The following is a translation of his principal 
statements:— 
“ The removal of a fine old tree may sometimes be neces¬ 
sary and useful, but it would be a mistake to seek to 
convert into a general rule what can only be a rare excep¬ 
tion. 'Whatever may be the merit of Mr. McGlaslien’s 
ingenious machine, we consider it unfitted to insure the 
subsequent success of every description of plantation, 
especially of those trees within the bounds of Paris. Not¬ 
withstanding the distinguished patronage which it has lately 
received, it can only be available in exceptional cases. 
Indeed, the transplanting of a tree, that is, its removal from 
one place to another, is only a small and very insignificant 
part of the operations incidental to its successful treatment. 
It is neither the lifting nor removal of a tree which forms 
the most important question in arboriculture, but its subse¬ 
quent growth and prosperity; and these results are the 
ordinary consequences of putting in practice those rules 
which true science indicates, and. which mature experience 
sanctions. 
Let me shortly observe, that in order to insure the health 
of trees after planting, the following directions should be 
carefully pursued:— 
1st. The holes destined to receive the trees should be dug 
a year or six months before the time of planting. 
2nd. If the soil is not sufficiently rich, it should be re¬ 
placed by fresh earth, containing the most numerous 
elements of fertility. 
At different times we have directed attention to the im¬ 
portance of using in the bottom and sides of the holes a 
prepared compost from three to four year’s old. This 
