MAGAZINE OF SCIENCE AND ART. 
33 
pN EXPERIMENTS WITH SILKWORMS WITH 
A VIEW TO IMPROVE THE PRESENT SILK 
YIELDINGS OF BENGAL. 
By F. Bashford, of Surdaii, East Indies. 
I have devoted ray attention to silk reeling in Bengal 
for nearly twenty years, and JjavVlaboured hard to pro¬ 
duce a thread as fine, as perfect in the reel, and as well 
suited for manufacturing purposes in Europe, as French 
and Italian silk. I have succeeded so far as to merit 
the Medal of the Society'of Arts, for my comparatively 
superior quality'over other Bcngals, none for many years 
past approaching Surd ah (J. and R. W. Mark) by 
several shillings per pound in value. My reel has con¬ 
siderably surjmssed China, and como up very (dose in 
the finer sizes to middling Italian in jts various appli¬ 
ances and value, as a reference to any price current or 
manufacturer in England or Lyons will corroborate; 
still I find that I am far behind the finest siy.es of both 
France and Italy, ahd with a view to approach more 
nearly to them 1 have imported eggs of the finest cocoons 
reared in both countries, with a view to engraft them 
upon the different species of worms indigenous or at 
present common in Bengal, and 1 received also a large 
.quantity of the best China eggs with the same view, as 
the cocoons of that country are also sunorior to all wo 
jhave in Bengal, although their silk is inferior. 
1 am desirous to givo : the result of my exertions to 
the public, as it may be a gpido to others ; and the giv¬ 
ing myself this flattering introduction is to show that 
the experiments have been made by a practical man, 
who has charge of forty filatures, working 4,500 basins, 
and therefore interested in the favourable results of 
such experiments, and in any good that may accrue from 
dhe publicity of these remarks. 
To enable my readers to understand the subject tho¬ 
roughly, I will commence by mentioning that all our 
worms in Bengal for filature silk give us several crops 
of cocoons during the year, except a solitary species of 
annual, origin unknown, and rapidly becoming cx- 
‘tinct. 
The chief worm is what is called the dcssie, or, as 
4he word implies, country,—anti I therefore conclude it 
to bo aboriginal or indigenous; it supplies nearly all 
the cocoons of the large November bund, or cold wea¬ 
ther crop of Bengal, and yields the finest silk ; the 
cocoons are small, and it is therefore sometimes called 
,the chota poloo, or small worm in some districts : the 
produce of the best quality may he taken at about 
10,500 cocoons to tbo pound of silk ; this worm thrives 
-best in the cold weather, and the cocoons are better then 
.than the after crops, hut it continues more or less in the 
different districts throughout the year r the period from 
'the hatching of the egg till the completion of the cocoon 
.of this worm is about thirty-six days in the cold wea¬ 
ther, but much less as the heat- increases. 
The next species of importance, is the madrassie ; the 
native meaning of the word is seaborn, and I therefore 
conclude this to be an important species; it is some¬ 
times called nystree i it is produced throughout the 
year, but thrives much the best in the hot weather, from 
"March to September, is remarkably hardy, and easily 
and economically reared; from tins species wo derive 
in the March and rainy bunds a very large supply of 
cocoons; the produce is comparatively better than that 
of the dessie, about 10.000 of the best cocoons being re¬ 
quired to produce one pound of silk, but the fibre is 
neither quite so strong, nor the colour so bright, though 
: it nevertheless produces a very good thread if carefully 
reeled; these worms pass through their stages so ra¬ 
pidly, that from the time of hatching to the completion 
of the cocoon -is frequently not over 25 days, Thus, 
you see, two distinct species of cocoons are providen¬ 
tially arranged for our different seasons, 
The next is the boro polo, or in English—large worm. 
This is an annual, and I cannot trace its origin ; it 
existed when the East India Company first imported 
Italian eggs, all of which soon failed. The boro polo is 
now chiefly found in the Radnatroro district, and from 
this worm they get much of their March bund ; but it 
is failing fast; it used to exist in other districts, and tho 
silk from it was very beautiful, and the produce nearly 
double that of other cocoons, hut from frequent failures, 
irregular hatching, and greater expense in reariug, and 
being an annual worm oulv, the natives have taken a 
dislike to it, And I fear it wil l soon be as scarce in Rad- 
nagore as it now is in other districts ; they have another 
species of worm in lladnagore, called the China, hut 
how it acquired that name I do not know, as in China 
their worms arc annuals, and this is not; the cocoon is 
certainly unlike in shape and very inferior to the China, 
and even inferior to our dessie and madrassie. I havo 
now described the best species of our Bengal silkworms, 
and I have shown that it requires 10,000 of our best 
cocoons to nroduce me one pound of good silk; in 
France 2,500 cocoons produce the same quantity of silk. 
This disparity in produce between the Bengal and 
European cocoons must for ably strike every reader of 
this paper, and tho natural suggestion will be, that if 
Bengal could produce cocoons equal to French and Ita¬ 
lian, the quantity of worms they now rear would nearly 
supply the whole of Europe with silk. 
Actuated by a desire to improve our cocoons, and 
seeing no reason to doubt the possibility of it, in a 
country so beautifully supplied -with mulberry and every 
convenience for rearing worms as this is, I imported a 
large quantity of the best French, Italian, and China 
eggs to engraft upon the different puny species of our 
Bengal monthlv race. 
1 had no desire to introduce an annual, as this is a 
worm only intended hv nature for cold climates, where 
thero is but one crop of mulberry in the year; here, wo 
no sooner cut down our bush mulberry, than it springs 
up again, and in five of six weeks we have a second lux¬ 
urious crop ; in a country, therefore, so bountifully and 
continually supplied with mulberry, an annual worm 
(which at best is always irregular) is not required, and 
would not be encouraged by the natives. 
I imported the annual eggs merely for one crop of 
cocoons that I might have the moths to couple and cross 
upon our Bengal monthly race, and give new strength 
and vigour to that. I now proceed to explain the nature 
of ray experiments, and their results. 
In February, 1854,1 received per overland a largo 
quantity of the best French silkworms’ eggs; they were 
however indifferently packed, and only 5 or 6000 eggs 
were good out of a very large parcel; some of these 
commenced hatching about 15 days after the box was 
opened, with the thermometer ranging^ from 60 to 70 
Fahrenheit, and they continued hatching very irregu¬ 
larly for about three months, during which time tho 
thermometer at midday reached about 100 in tho 
house. 
I treated tho little worms precisely as the worms of 
this country, feeding them at first with finely-cut tender 
mulberry leaves, giving the larger and older leaves as 
they increased in size and strength; they fed and 
thrived very well, displayed a better constitution, and 
more hardy nature than our country worms; their 
stages of sickness were in tho colder weather at six to 
eight days interval, but move rapid as the heat became 
greater; they got over them verv well, and but few 
died until near the time of spinning, when the usual 
disease attending our country worms attacked some of 
these, from' which they chiefly died, recovery being 
very rare; As we havo no remedy for these diseases 
the usual fumigations were tried, but with little 
success. 
The healthy few of the early incubations, astonish¬ 
ingly large and strong compared to our country stock, 
were placed to spin in mat frames, such as are used by 
the natives in their rearing establishments (as I used 
them from the begimJing to become habituated to the 
Very convenient custom of this country), and they gave 
very beautiful cocoons, some quite equal in size, shape, 
and firmness to the samples received with the eggs, and 
seemed to spin in our frames, as easily (these mat 
