330 ON THE PRODUCTION OF 
of preventing the passage of any noxious insect into 
the manchons. The silkworms are then placed on the 
top of the tree, by the upper opening of the canvas, 
which is then tied up with a string, care being taken 
to cover with wadding all the interstices which are 
left by the folds of the canvas where it is tied up. 
This operation being completed, two stakes must be 
firmly stuck in the ground, right and left of the 
manchon, and a strong string tied across, from the top 
of one to the other. To this string the top of the man- 
chon must be fastened, so that it may not press upon 
the top of the tree ; this contrivance will also prevent 
its displacement by the wind. 
Dr. Chavannes, in his work, advises the placing of 
the silkworms in the manchons at the second age only, 
and their removal when they are at the fifth age, to< 
make them cocoon in'the magnanerie. 
As I have stated above, I have carried my practical 
experiments much farther than Dr. Chavannes, and, 
after the convincing proof of several years' experience, 
I can maintain that in our climate the silkworm may 
be born, live, and cocoon, the moth be formed, couple, 
and lay its eggs upon the tree. I will also mention 
that every year I let a certain number of moths lay 
their eggs on the branches of the mulberry. This, 
grain remains there during the winter, exposed to all 
external changes of weather, and simply protected by 
the manchon from noxious insects. In the spring this 
grain is hatched perfectly, and very vigorous silkworms 
are produced from it. 
To this hybernation on the tree, which I have prac- 
tised for several years past, I attribute the exception- 
ally robust health of the race which I rear. 
