Penicillium is a plant which is distributed widely and apparently is
able to grow wherever organic matter is found, though flourishing
best when the material contains acid. It causes loss in canneries,
breweries, distilleries, etc., the only use made of it being in the
manufacture of Roquefort cheese, the immature cheese being inoculated
with the conidia for the effect the mold produces in the maturing
process.
[Illustration: Fig. 1.--Conidia, Normal Size and in Various Stages of
Germination, Some with Branching Hyphæ (× 325).]
[Illustration: Fig. 2.--Conidiophore, Showing Unusually Large
Development of Conidia, from Culture in Moist Chamber (× 325).]