CHAP. C. URTICA‘CEE. MoO‘RUS. 1357 
spirits, the gum having been dissolved by the spirit. The whisk is then moved lightly about till 
the filaments adhere to it, and are drawn off. As soon as a sufficient number are collected, the 
reeling begins, (See Amer. Silk-Grower’s Guide, Murray onthe Silkworm ; Nouv. Cours d’ Agric., &C.) 
If well fed, in a proper temperature, the caterpillars will have finished their labours in 24 days from 
the period of being hatched; and the quantity of silk produced will, other circumstances being 
equal, be in proportion to the quantity of food devoured: its quality will depend on the climate and 
soil in which the leaves have been grown. An ounce of eggs will produce about 40,000 caterpillars, 
which will consume 1073 lb. of leaves, and produce 80 lb. of cocoons, or about 8 lb. of raw silk. The 
worms are subject to numerous diseases, the most fatal of which is vulgarly called the tripes ; and 
is brought on by wet or improper food. When any insects appear sick, they should be immediately 
removed from the rest, as all their diseases appear to be contagious- Wet leaves should never be 
given to silkworms, as they occasion disease ; and it is better to let the insects fast for 24 hours, 
or even longer, than to give them leaves that are not perfectly dry. In wet weather, the branches 
of the tree should be gathered, and hung up ina dry place; or the leaves should be gathered, and 
spread outto dry. ( Nouv. Cours d’Agric., vol. xvi. p. 103.) 
Substitutes for Mulberry Leaves in feeding the Silkworm. It is probable that the leaves of all the 
plants that contain a milky juice will, if they are eligible in point of texture, afford suitable food 
for the silkworm, from the common property of milky juice, that of containing caoutchouc. 
Accordingly, trials have been made with the tender leaves of the fig, with the leaves of tle maclura, 
and of A‘cer platanéides and A. tataricum, among trees ; and of lettuce, endive, beet, spinach, nettie, 
&c., among herbaceous plants. None of these substitutes, however, are of any real use, unless we 
except the maclura and the lettuce. The former, according to the American Gardener’s Magazine, 
is thought likely to answer to a certain extent; as the lettuce and endive have done formerly, more 
especially when the plants have been allowed to send up their flower stalks before their leaves were 
gathered. In 1792, a Miss Croft of York sent a specimen of silk of her own rais'ng to, the Society 
of Arts, the worms producing which had been fed entirely on lettuce leaves. 
Soil, Situation, Propagation, and Culture. The white mulberry is more 
tender than Morus nigra, and requires more care in choosing a situation for 
it. Calcareous soil is said to produce the best silk; and humid situations, or 
where the roots of the tree can have access to water, the worst. A gravelly 
or sandy loam is very suitable ; and trees grown on hilly surfaces, and poor 
soils, always produce superior silk to those grown in valleys, and in rich 
soils. The tree is propagated by seeds, cuttings, layers, and grafting. To 
obtain seeds, the berries must be collected from trees which have been 
known to produce male catkins the preceding spring. The berries are 
either gathered when quite ripe, and left to become dry before the seed 
is separated from them; or they are put into water as soon as gathered, 
and rubbed so as to separate the seeds, which are cleansed from the pulp 
in the water, and then rubbed dry on a linen cloth, and either sown im- 
mediately, or mixed with sand, and kept till wanted for use. In the south 
of France, the seeds are sown as soon as the fruit is gathered, and the plants 
come up the same autumn; but, in colder climates, they are kept till spring, 
when they generally come up in three or four weeks, and require some pro- 
tection, at first, during cold nights. In Germany, and in the north of the 
United States, the young plants are covered, during the first winter, with dry 
leaves or straw; and this covering, or mulching, is continued on the ground 
for three or four years, till the plants are thoroughly established, to protect 
their roots from the cold. The young plants are generally taken up and 
replanted the second spring, care being taken to place them in rows 4 ft. 
asunder, for the convenience of gathering the leaves. AZ. a. multicailis is always 
propagated by layers or cuttings ; the layers being made in spring or at mid- 
summer, and separated from the mother plant in autumn ; or by cuttings of 
branches, or truncheons, which will root readily, and produce leaves for the 
worms the following year. Count Dandolo recommends grafting the species 
with the large-leaved varieties, near the ground, the third spring; but most 
writers on the silkworm appear to prefer seedling plants, or plants raised 
from layers or cuttings, to grafted ones. In pruning, cutting in, or heading 
down, the trees, the great object is to preserve the equilibrium of the heads, 
so that the sap may be equally distributed through the branches on every 
side. On this depends the production of a crop of leaves of equal quality on 
every part of the tree, which is alike important both for the first crop, which 
is given to the worms, and for the second crop, which is required for the 
nourishment of the tree. 
Insects and Diseases. The leaves of the white mulberry are eaten by no 
insect but the silkworm : it is, however, attacked by numerous diseases, partly, 
no doubt, occasioned by the unnatural manner in which it is treated, by being 
stripped of its leaves. One of these diseases is brought on by any sudden 
