32 
THE ART OF REARING 
weight, without considering that it is neither the 
water nor the fibre of the leaf that nourishes the 
silk-worm, and renders the cocoon heavy, but the 
resinous and saccharine substances which I have 
mentioned in the foregoing pages. 
There is another fact to be observed ; that, in 
equal circumstances, an old mulberry tree will 
always produce better leaves than the young tree ; 
and moreover, as the tree grows older, of what- 
ever quality it may be, the leaf diminishes in size, 
and improves so materially, that it at last attains 
a very excellent quality. I have hitherto only 
treated of the leaves of the grafted mulberry ; the 
leaf of the wild mulberry is that which, in equal 
weight, contains, in the greatest proportion, both 
the nutritive and silky substances. This leaf, in a 
smaller quantity than that of the grafted mulberry 
leaf, offers a much more satisfactory result. I 
know not whether any one has made, with exact- 
ness, and upon a large scale, this important com- 
parison. (Chap. XI.) 
Another view of the subject, which must not be 
overlooked by the cultivator, is, that the grafted 
mulberry, particularly when old, produces a much 
greater quantity of the fruit than the wild tree. 
This fruit, which the silk-worm generally does 
vides for the very great evaporation which takes place in the 
body of the young silk-worm, in the first and second stage, 
for reasons which I have detailed elsewhere. 
