PARASITIC FUNGI AND MOULDS. 51 
into chrysalides are only thrown away when they are 
found on removing the cocoons. The clouds of dust 
dispersed by the silkworms perpetuate the disease 
in the best-ordered factories. When the heather is 
thrown out of window, and the rooms are swept to 
get rid of the dust, the spores float in the air and 
are dispersed by the wind. 
Damp favours the development of the fungus, and 
the introduction of healthy silkworms into an infected 
breeding-house will not extirpate the disease. In order 
to attain this object, it is necessary to get rid of all 
the dead silkworms before the development of the 
spores, and to destroy their bodies by burning them 
with the heather, or with quicklime. The breeding- 
houses should then be completely emptied, and the 
compartments should be purified and disinfected in 
the ordinary way by fumigation with sulphur, and 
washed with chlorine water, before fresh silkworms are 
placed in them. 
IX. Parasitic FuNGI OF THE SKIN AND Mucous 
MEMBRANE OF MEN AND ANIMALS. 
The skin-diseases of man and animals which are 
termed tinea are caused by the presence of parasitic 
fungi, just as the itch is produced by the presence 
of animals belonging to the group Acarus. These 
diseases are rendered eminently contagious by the 
dissemination of the spores of these fungi, which will 
