222 REPORT OF THE COMMISSIONER OF AGRICULTURE. ~ 
‘ 
though it attacks worms of all ages, it is by far the most fatal in the | 
fifth or last age or stage, just before the transformation. 
“This disease was proved by Bassi to be due to the development of | 
a fungus (Botrytis Bassiana) in the body of the worm. It is certainly 
infections, the spores, when they come in contact with the body of the 
worm, germinating and sending forth filaments which penetrate the 
skin, and upon reaching the internal parts give off minute floating 
corpuscles, which eventually spore in the efflorescent manner described. 
Yet most silk-worm raisers, including such good authorities as E. F. 
Guérin-Méneville and Eugene Robert,* who at first implicitly believed 
in the fungus origin of this disease, now consider that the Botrytis is 
only the ultimate symptom—the termination of it. At the same time 
they freely admit that the disease may be contracted by the Botrytis 
spores coming in contact with worms predisposed by unfavorable condi- 
tions to their influence. Such a view implies the contradictory belief 
that the disease may or may not be the result of the fungus; and those 
who consider the fungus as the sole cause certainly have the advantage 
of consistency.” Dr. Carpenter, of microscopic fame, believes in the 
fungus origin of the disease, and thinks it entirely caused by floating 
spores being carried in at the spiracles or breathing orifices of the worm 
and germinating in the interior of the body. 
Whichever view be held, it appears very clear that no remedies are * 
known, but that care in procuring good eggs, care in rearing the worms, 
good leaves, pure, even-temperatured atmosphere, and cleanliness, are 
checks to the disease. The drawers and other objects with which the 
diseased worms may have been in contact should be purified by fumi- 
gations of sulphurous acid (SO,), produced by mixing bisulphite of 
soda with any strong acid, or, better still, by subjecting them to a car- 
bolic-acid spray from an atomizer. In this way all fungus spores will 
be destroyed. In fact it will be well to wash off the trays or shelves 
once in a while with diluted carbolic acid, as a sure preventive. It is 
the best disinfectant known to science. The cheapest kinds may be 
used with the same efficacy as the more expensive. 
Another disease, known as pébrine, has proved extremely fatal in 
‘Southern Europe, and for twenty years has almost paralyzed silk-eult- 
ure in France. It is a disease which, in its nature and action, except 
in being hereditary, bears a striking analogy to cholera among men. 
“The worms affected by pébrine grow unequally, become languid, lose 
appetite, and often manifest discolored spots upon the skin. They die 
at all ages, but, as in muscardine, the mortality is greatest in the last 
age. The real nature of this malady was for a long time unknown. In 
1849, M. Guérin-Méneville first noticed floating corpuscles in the bodies 
of the diseased worms. ‘These corpuscles were supposed by him to be 
endowed with independent life, but their motion was afterwards shown 
by Filippi to depend on what is known as the Brownian motion, and 
they are now known either by the name of panhistophyton, first given 
them by Lebret, or by that of psorospermia. ‘They fill the silk canals, 
invade the intestines, and spread throughout the tissues of the animal 
in all its different states; and though it was for a long time a mooted 
question as to whether they were the true cause or the mere result of 
the disease, the praiseworthy researches of Pasteur have demonstrated 
that pébrine is entirely dependent upon the presence and multiplication 
of these corpuscles. He bas analyzed the disease so clearly that not 
only do we see its nature, but are able to point out the remedy. The 
*Guide & V’aléveur de vers e soie. 
