Restoration of the Silkworm. 149 
changed or lost its colour under domestication, would in all pro- 
bability never enter into the head either of the Chinaman or of 
his interrogator. Seeing then, as I shall presently show, that the 
Eastern is infinitely inferior to the European stock, the crossing 
with seed selected either in India or in China would only be 
adding to the disease which already threatens the West with such 
disastrous consequences. 
Nature of Experiments explained. 
I may, however, be asked, what proof I can adduce of disease 
and change of colour? As regards the existence of disease there 
is no occasion to reply, as the fact is only too well known; but as 
regards the loss of colour, I have abundant evidence now before 
me. 
All those, indeed, who have had the least experience in the 
rearing of the silkworm must have perceived the occasional occur- 
rence among the brood of one or more dark-grey or blackish- 
brindled worms, contrasting strongly and curiously with the pale 
sickly hue of the majority. These, by the French cultivators, are 
called “vers tigrés” or “ zébrés,” that is, ‘tiger or zebra striped,’ 
and are regarded as a mere variety. Yet these are, in fact, the 
original and natural worms ! 
My attention having long since been arrested by this circum- 
stance, it at length occurred to me to endeavour by a series of 
experiments to ascertain the cause, my conviction being, either 
that the species had at some time or other been crossed by another 
of different colours, and that nature, as sooner or later she always 
will do, was making an effort to separate them; or that the 
original colour of the worm had in reality been dark, and an effort 
was being made to revert from a sickly condition to the original 
healthy starting-point. Acting on this idea, I at once determined 
to assist Nature by giving her fair play, and, consequently, picked 
out all the dark-coloured worms and reared them separately, 
allowing the moths to couple only inter se, and the same course 
was pursued with the white worms. 
In the following spring the one batch of eggs produced nearly 
all dark-brindled worms, while the other produced white ones, 
sparingly interspersed as before with an occasional dark one; 
these latter were removed into the dark batch, which was at the 
_ same time weeded of its pale worms. 
In the third year the worms were still darker than before, and 
were always larger and more vigorous than the pale ones, giving 
likewise larger and better stuffed cocoons, 
M 2 
