from an Agricultural and Veterinary Point of View. 71 
The corpuscles contained in the eggs alone caused the trans- 
mission of the disease to future generations ; and thus it was both 
contagious and hereditary. 
Pasteur had demonstrated that moths free from corpuscles 
produced eggs also free from them ; and also that eggs hatched 
at a distance from infected eggs produced healthy worms, 
chrysalides, and moths. It was easy, therefore, to multiply 
cultivations free from the disease ; and to secure the production 
of silkworms and silk, to guarantee that the eggs were sound, 
Pasteur recommended that a moth should be crushed up in a 
little water, which is then examined with a microscope to 
ascertain if any corpuscles are present. 
In his investigations, Pasteur soon recognised that there was 
another disease at work, no less destructive, though less widely 
spread, than the so-called pehrirtc. During his experiments, 
in a cultivation of say a hundred worms, a large number, as 
many sometimes as twenty, would be picked up daily ; these 
turned black and putrefied within a few hours, being soft, flabby, 
and hollow ; they were free from the pcbrine spots, and no cor- 
puscles could be found in them, while these organisms were also 
absent from the chrysalides and the moths of the few worms 
which were able to spin their cocoons. Pasteur was certain that he 
had to deal with a distinct disease, and that this was one known 
to French writers upon silkworms by the name of flacherie, or 
moi-ts-flats. The cultivations most seriously affected by the 
malady came from eggs yielded by moths entirely free from 
corpuscles. Microscopical examination settled the question. 
If, at the period of rearing of silkworms, which happens when 
the mean temperature of the air is high, some mulberry-leaves 
are crushed with a little water in a mortar, and the liquid 
allowed to stand for twenty-four hours, it will be found to be 
teeming with microscopic organisms— some motionless, resem- 
bling little rods or spores joined like strings of beads ; others, 
flexible and moving about in a sinuous manner, like the 
vibrions found in nearly all decomposing organic infusions. 
The germs of these organisms were on the surface of the leaves 
before they were pounded, in the water, or on the pestle and 
mortar. So long as the intestines of the worms were healthy, 
the germs were either digested or expelled without causing 
damage ; but whenever digestion was impaired, which, with 
such a ravenous creature, and rapidly growing, might be fre- 
quent, then the disease appeared. " Every ver fiat (flattened 
instead of round) is one which digests badly, and, conversely, 
every worm which digests badly is doomed to perish of 
Jiacherie, or to furnish a chrysalis and a moth, the life of which, 
