168 Captain T. Hutton on the 
and more frequent supply. A good and healthy leaf should con- 
tain the four ingredients of fibre, water, saccharine and resinous 
matter; the two first go directly to the nourishment and growth 
of the worm, while from the two latter is secreted the supply of 
gum which eventually furnishes the silk. Where the two former 
only are found, or where they are greatly in excess, as is some- 
times the case, the worm will grow and attain to a goodly size, 
but will produce little, or perhaps no, silk. In breaking off a good 
healthy leaf, a drop or two of thick milky viscous juice should 
exude from the stalk, and in this resides the silk-producing 
matter; the Morus Sinensis and all the thick-leaved trees possess 
this in far greater quantity than either 2/7. cucullata or M. multi- 
caulis, and indeed from the latter species, when grown in a cold 
climate, it is almost absent, being thin and watery. 
Yet after all, it has long since been laid down as an ascertained 
fact, that however much the quantity of silk may be dependent 
upon the presence of this juice, the quality is far less dependent 
upon the good properties of the leaf than upon the temperature in 
which the worms have been reared; so that where this is higher 
than the constitution of the insect is fitted to endure, no matter 
how well it may have been fed, the yield will always be inferior to 
that produced in a more genial temperature ; and that the Bombyx 
Mori of Cashmere is greatly influenced even by the heat of the 
Punjab, is proved beyond all contradiction by M. Perrottet’s ob- 
servation, in epistold, that eggs deposited there and sent to him by 
Mr. Cope, of Umritsir, were inferior in size, and far more irregu- 
lar in form, than those sent by me from Mussooree, where the 
climate is better adapted to the species. The fact is moreover 
fully established by the annual loss sustained by Jaffer Ali as 
above narrated, as well-as by Mr. Cope’s expressed intention of 
sending his Punjab-bred eggs to the hills during summer, and of 
importing annually fresh seed from Cashmere. The same remark 
is equally applicable to Oudh. 
That the thinness of the leaf, both in M. multicaulis and M. cu- 
cullata, is a very serious defect may be gathered from Count 
Dandolo’s remark, that “the less nutritive substance the leaf 
contains, the more leaves must the silkworm consume to complete 
its development. The result must, therefore, be that the silkworm 
which consumes a large quantity of leaves that are not nutritive, 
must be more fatigued and more liable to disease than the silkworm 
that eats a smaller proportion of more nutritive leaves. The same 
may be said of those leaves which, containing a sufficiency of 
nutritive matter, contain little resinous substance; in that case 
