Address of Professor Husley. 399 
smallest germs of the Hmpusa got into the fly. The spores 
could not be made to give rise to such germs + cultivation ; 
nor were such germs discoverable in the air, or in the food of 
the fly. It looked exceedingly like a case of Abiogenesis, or, 
at any rate, of Xenogenesis; and it is only quite recently that 
ts é + has been 
because the spores become scattered about all sorts of matter in 
the neighborhood of the slain flies. 
he silkworm has long been known to be subject toavery 
fatal and infectious disease called the Muscardine. Audouin 
transmitted it by inoculation. This disease is entirely due to. ~ 
. the development of a fungus, Botrytis Bassiana, in the body of — 
’ the caterpiller; and its contagiousness and infectiousness are — 
accounted for in the same way as those of the fly-disease. But _ 
of late years a still more serious epizodtic has appeared among 
the silkworms ; and I may mention a few facts which will give 
you some conception of the gravity of the injury which it has 
inflicted on France alone. 
The production of silk has been for centuries an im 
branch of industry in Southern France, and in the year 1853 it 
had attained such a magnitude that the annual produce of the 
French sericulture was estimated to amount to a tenth of that 
e working up of the raw silk thus produced 
is more than I can pretend to estimate. Suffice it to say that 
the city of Lyons is built upon French silk as much as Man- 
chester was upon American cotton before the civil war. 
