Restoration of the Silkworm. 169 
the insects would thrive and grow, but probably would not pro- 
duce either a thick or strong cocoon proportionate to the weight 
of the silkworm, as sometimes occurs in unfavourable seasons. 
My experiments,” continues the Count, ‘prove in the ultimate 
analysis that, all things balanced, the qualities of the soil produce 
but a very slight difference on the quality of the leaf; that which 
will appear most evident is, that the principal influential cause of 
the fineness of the silk is the degree of temperature in which the 
silkworm is reared. It is neither the water nor the fibre of the 
Jeaf that nourishes the silkworm and renders the cocoon heavy, 
but the resinous and saccharine substances.” 
The concluding sentence, however, is scarcely to be relied on, 
since the worm in its growth is undoubtedly nourished by the 
water and the fibre of the leaf, although it is equally true that the 
weight and thickness of the cocoon depend upon the presence of 
the other substances, while it is necessary to guard against the 
error of endeavouring to produce too much fineness in the silk, 
since I have already shown that to be an indication of too high a 
temperature and of the consequent degeneracy of the worm. 
Besides which, that the soil must in some measure act upon the 
quality of the leaf can scarcely be doubted when we consider that 
it is from the soil that the tree derives its nourishment, and the 
changes which occur both in the shape and substance of the leaf 
and in the colour of the fruit can be attributed, I imagine, to 
nothing else. 
In regard to the treatment of the trees, it has been justly re- 
marked that they may be very seriously injured by too close 
plucking; it has been forgotten, however, by those who in India 
have laid some stress upon the fact, that the remark applies rather 
to the mulberry trees of Europe and other temperate climes, than 
to those of tropical regions; for in the former there is too short a 
summer to enable the tree to produce fresh leaves without an 
injurious effort on the part of Nature;* whereas in tropical and 
neighbouring climates, where the summers are warm and long, 
and otherwise conducive to the growth of vegetation, the dread 
of injury need scarcely be entertained. Nature, indeed, herself 
points out that such is the truth, for in the Himalaya the indi- 
genous mulberry trees may often be seen in the early part of May 
without a single leaf upon them, all having been devoured by the 
first or spring-brood of the larvee of Bombyx Huttoni ; and yet in 
* Mr. F. Moore informs me that eggs of B. Huttoni hatched in April, when 
there were yet no leaves! 
