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nature and food of the different species of silk-producing 
lepidoptera, and given the results to the public. In this 
country the Society of Arts have agitated the question, and 
published several articles upon the Bombyx Cynthia, in their 
journal. It is, however, to Herr Ernest Kaufrnann, the chief 
merit is due, as from numerous experiments and transmission 
of the eggs of the Bombyx Ricinus or Cynthia to various 
individuals, he has done more than any other person to 
ensure the accomplishment of this new branch of industry. 
Professor Kaufrnann delivered a report on the comparison 
between the growth of Ricinus and Mulberry Silk, before 
a general meeting of the Acclimatisation Society of Prussia, 
on the 22nd Oct., 1858, from which I have derived the 
most important information on this subject I am about to 
bring before you. 
The first fact alluded to by Kaufrnann is highly important 
as regards the cultivation of the Assam Silkworm, which is, 
that seldom more than one brood of the common Silkworm 
(Bombyx Alori) can be successfully reared in one season in 
Germany or Prussia. Further south, the mulberry, if 
prudently divested of its leaves, will reproduce a quantity of 
foliage sufficient to supply a second brood with advantage. 
But in more northern latitudes, where the vegetation is less 
vigorous, a second crop can scarcely be expected. The 
cidtivator, therefore, must be satisfied with one brood of eggs 
only, of which every healthy female will lay from 400 to 
500. The number of eggs laid by the Assam Silkworm, 
however, is not so great, seldom above 300. But this is com- 
pensated for by the circumstance that the insect goes through 
its series of transformations in about six weeks, and it is, 
therefore, possible to obtain eight or nine broods from a single 
pair in the course of one year. The author gives an approximate 
estimate of the enormous quantity of cocoons to be derived 
from a single pair of this moth, in so short a space of time, 
