Evening star. [volume] (Washington, D.C.) 1854-1972, 1904-08-11
FEDON COLOREDLEAVES
THEIR OWN PRODUCT.
Development Of New Process III
France as Explained by U. S.
Consul Covert.

If is the age of marvels. Color pho
| Biography and silk colored by the worm
| itself are the latest. Both OF these won
! ders come from Europe, strange to say,
| and not from the land of inventors
| America.
| Messrs Comte and Levrat of Lyons.
! France are credited with the discovery
of the method by which silk worms can
| be induced to spin cocoons of SILK colored
| in various hues. This obviates the ne
| cessity of dyeng the silk in the piece or
the thread but it is not expected that the
discoveries will cause great changes in
| the industry of silk dyeing, since the lat
ter work is carried on on a much larger
scale than can at present be operated
with the worms themselves
In an interesting report on the subject
| to the Department of Commerce and Labor
| United States Consul John c. Covert sta
| toned at Lyons. says that the principal
| point of interest in the experiments is not
| the effect upon an ancient industry, but
| the manner by which the naturally dyed
| silk is obtained from the worm. The field
| has been partially worked for the last
sixty years, the object being to discover
| why some breeds of silk worms produce
white silk while others produced a silk of
| a yellow or a yellowiSh green color. The
| discovery has been made that the natural
| coloring matter of the cocoons was
| identical with the coloring matter found
| In tUS leaves eaten by the worms. 1t
| was. therefore, logical to believe that the
color of the silk must originate in the
chlorophyl of the leaves fed to the worms.
Experiments Made.
| Experiments undertaken to test this
| hypothesis proved that a coloring mat
| ter introduced into the intestines of the
| worm by means of food may, under GER
| tain conditions, reach the silk through
| the blood
| Thirty silk worms were Matched in
June, 1903 and divided into number Of
| squads, one squad being fed on leaves
| dipped in liquid to color them. Some of
| these colored leaves were light red, and
| the worms ate them as they would have
| done ordinary leaves, growing and de-
vetoping on them well as upon their
| natural food. The general color of their
| bodies became Il dark red and their blood
| was an intense RED.
| Early in August the cocoons We're form
| ed and pink silk was reeled from them,
the entire cocoon being of a beautiful red
| color To prevent the silk from. being
| soled from contact with the coloring
matter on the leaves or by the skin of
| the worms, which might have been spot
| ted by the dye some of the worms were
washed and placed on freshly gathered
| branches where they at once began to
| form cocoons as red as the first lot.
| Two worms which had been eating col
| ored leaves We're separated from the others
| at the fourth moulting. in July and fed for
the rest of their lives on uncolored leaves.
| They gradually lost the color received from
the colored leaves, and the silk reeled from
them had only the slightest tinge of rose.
The color of these worms was completely
| lost in eighteen days.
The worms selected from the lot at the
| fourth moulting We're fed on colored leaves
only during the fifth period of life and
they rendered, in August cocoons as red
as those of the first lot, in which the worms
| had been fed on colored leaves during tn,
4S,n I4~
during the last period is therefore necessary
and sufficient to color the silk
fourth lot was composed of worms fed
| on methylene blue. They ate this with less
avidity; and a number, in their efforts to
escape this food. fell from the branches
| and were lost The formed their cocoons
slowly and rendered but little silk, which
| was of slightly blush color.
Another lot of worms, the Atticus orizaba
| (ths is a wild worm which does Tot cat
mulberry leaves) were fed on leaves of the
troene. tree of the olive family These
leaves were dipped in a solution Of picric
acid. The well-known toxic qualities of
that coloring matter did not prevent it from
being eaten, but the worms did not relish
1T keenly and made no cocoons until Sep
| TENDER 4. Notwithstanding the coloring
power of picric acid the silk remained
white
Thus see that the neutral red passes
easily by osmosis through the tissues while
methylene blue passes with difficulty. and
picric acid leaves no trace of color.
Varying Results.
The varying results of the different ex-
periments are due to the different coloring
| matter tried. The well-known properties
of the neutral red and the methylene blue
| in coloring tissues marked them for exper-
! iments of this kind. AS to the picric acid
| its absorption by the worms seemed to be
so strange that the workers were led to
carry on their experiments to the end. In
order to give careful answer to particu-
lar inquirers, inspired by the belief that
the thread was possibly soiled by contact
with the coloring matter. simultaneous
injection was made, In the worms ready
to form their cocoons, in the false feet so
as not to injure any organ. These worms
Immediately became red, without appear
ing to suffer in the least. They produced
| a slightly reddish silk.
The experiments demonstrate that the
infection of coloring matter into and
through the sericigene gland is less easy
with the bombyx (black bombyx is a do
nestle worm that feeds on the mulberry
than with the Attfcus orfzaba.
From the Investigations and experiments
moAe % 10 in9efrod that q c0l0ring matter