CHINESE MODE OF REARING SILKWORMS. 139 
fully dried in the sun, and used by this people in 
preference to every other kind of fuel. 
Those practised in the rearing of silkworms say, 
that the sooner they can be brought to a state of 
maturity the better ; and that the quantity of silk 
which they produce is more or less as they are able 
to effect this. It is considered that the worms are 
most productive when they are fully fed, in from 
twenty to twenty-five days; in which case that 
each drachm weight of eggs will eventually produce 
about twenty-five ounces of silk ; and that, if their 
maturity is protracted till the twenty-eighth day, 
that only twenty-one ounces are produced by the 
same quantity of eggs ; and if they are not full fed 
hefore the lapse of thirty or forty days, that not 
more than ten ounces of silk will be the produce of 
the above quantity of eggs. 
The Chinese say that much depends upon the 
mode of feeding, in promoting or retarding the 
growth of silkworms. To ascertain this, we tried 
an experiment in the summer of 1833, on some 
caterpillars of the Cabbage Butterfly (Pontia Bras- 
sicce,) the Papilio Brassicce, volume first, page 186, 
which had been newly hatched. These we divided, 
and placed in two separate tumblers, and put them 
upon cabbage leaves. We supplied the larve in one 
of the tumblers plentifully twice a-day with fresh 
cabbage leaves, while those in the other tumbler 
had but a scanty supply, and even allowing them 
