916 
CURD-BREAKER. 
CURD-BREAKER. An implement or small 
hand-machine for breaking and comminuting the 
curd of skimmed-milk cheeses. It consists prin- 
cipally of a hopper for receiving the curd, a hard- 
wood cylinder studded with teeth, for cutting the 
curd, and a winch for turning the cylinder. It 
is held over a tub, and can be worked by a young 
boy or girl. It admits of being easily taken down 
and reconstructed, so as to undergo frequent in- 
ternal washing. 
CURL. A disease in potato plants. It is de- 
veloped before the plants rise to the surface of 
the ground; and it affects them through all the 
future stages of their existence. The stem of the 
infected plants is puny and stinted; the leaves 
are meagre, sickly, and crumpled; and the tubers 
are small, and, if used for sets, are certain to pro- 
pagate the disease. Curl takes its name from the 
crumpled appearance of the leaves of infected 
plants; and is readily recognised by every pota- 
to-grower in districts which it has at any time 
infested. It has often proved very devastative to 
| potato-crops throughout entire districts of good 
land, in excellent cultivation ; and it has rarely 
or never appeared in some other districts whose 
poor condition might have seemed to predispose 
the soil to its attack. 
Curl has been the topic of much ingenious 
speculation, and has been ascribed, by even acute 
and wise observers, to a great diversity of causes. 
Some writers ascribe it to the preying of insects 
| upon the sets and the young stems; others, to 
excessive seed-bearing ; others, to planting at 
either too small or too great depths; others, to. 
the influence of a late, frosty, and otherwise un- 
genial spring; others, to too early planting ; 
others, to too small cuttings; others, to an over- 
ripening of the tubers used for sets; others, to 
the oldness and dryness of the sets; others, 
to the exhaustion of the vital energy of the 
sets by the sprouting of the tubers from which 
they are formed; and others, to some local and 
hereditary but inexplicable influence. Of all 
these causes, the true one appears to us to be the 
diminution of the vital energy of the tubers 
either by over-ripening, by bad-keeping, by 
sprouting, or by too deep planting. The want of 
strength to develop a full healthy plant, is the 
disease itself in embryo; and this is occasioned 
by any circumstance which diminishes the store 
of nourishment contained in the tubers for the 
support of the young plants. See the article 
Buns. 
“No disease,” says Mr. George W. Johnson, 
“appears to me so evidently to arise from im- 
paired vital energy in the plant as the curl. Any 
one can insure the occurrence of this disease, at 
least I have found so in the county of Essex, by 
keeping the sets in a situation favourable to their 
| vegetation, as in a warm damp outhouse, and 
then rubbing off repeatedly the long shoots they 
| have thrown out. Sets that have been so treated, 
I have invariably found produce curled plants. 
CURL. 
Is not the reason very apparent? ‘The vital 
energy had been weakened- by the repeated 
efforts to vegetate ; so that, when planted in the 
soil, their energy was unequal to the perfect de- 
velopment of the parts; for the curl is nothing 
more or less than a distorted or incomplete for- 
mation of the foliage, preceded by an imperfect 
production of the fibrous roots.” He then details 
an experiment which both clearly illustrates and 
strongly confirms his views; and adds, “ Dickson, 
Crichton, Knight, and others have found that 
tubers, taken up before they are fully ripened, 
produce plants not so liable to the curl as those 
that have remained in the ground until com- 
pletely perfected; and I believe, under ordinary 
treatment, this to be the fact, for it is rational. 
The process of ripening proceeds in the potato, 
as in the apple, after it has been gathered ; and 
until that is perfected, it is accumulating vigour, 
shows no appetency to vegetate, consequently is 
not exhausting its vitality,—which is a great 
point, considering the careless mode usually 
adopted to store them through the winter,—for 
this energy commences its decline from the mo- 
ment it begins to develop the parts of the future 
plant. Tubers taken from the soil before per- 
fectly ripe, never are so early in showing symp- 
toms of vegetation. Crichton, Hunter, and 
Young have also agreed, that exposing the sets 
to light and air, allowing them to become dry 
and shrivelled, also induces the curl in the plants 
arising from them. This result of experience also 
confirms my conclusion, that the disease arises 
from deficient vital energy ; for no process, more 
than this drying one of exposure to the light and 
air, tends to take away from a tuber altogether 
the power of vegetating.” 
The means of preventing curl are distinctly 
suggested by the nature of its cause; and some 
of these means will, at the same time, prevent 
other diseases of the potato, and promote the 
general health and vigour of the plants. Tubers 
intended for sets ought to be simply matured and 
not over-ripened ; they ought to be kept, through- 
out the winter and till the time when they are 
wanted, in a condition of dryness, coolness, and 
exclusion from light and air; and if, through 
mismanagement or accident, they be allowed to 
shoot, or even to exhibit decided symptoms of 
begun vegetation, they ought to be rejected from 
the uses of planting. The sets ought to be plant- 
ed immediately after they are cut; and ought to 
be kept from exposure, during even the briefest 
time, to the play of sunshine, to a very high tem- 
perature, or to the current ofa drying wind. The 
manure ought to be regularly spread, and mixed 
with the soil, and not laid along a trench, or put 
in immediate contact with the sets. Potatoes 
ought not to be planted, for a succession of years, 
on the same field or plot; and the tubers used 
for planting ought, every year, or as frequently 
as possible, to be obtained from another kind of 
soil, particularly from a poorer one, than that in 
