If we study the vegetation of _aspergillus glaucus_ with this preconceived idea, we shall soon recognize the fact that these spherical forms of mycelium are the result of a greater or less deprivation of air. The filaments of this mycelium which develop freely in the aerated liquid are young and transparent, small in diameter, and exhibit the ordinary ramifications. Those which are situated about the centre, in the denser or more complicated parts, to which the oxygen cannot penetrate in consequence of its absorption by the surrounding parts, are more granular in appearance as well as larger, and inclined to develop swellings. We can observe no _conidia_[63] on these filaments, but we may say that they are on the point of appearing, for the spherical segments often tend to assume an appearance of close jointing, as when they take the form of those rows of swelling, or cells, which has given rise to the idea of the _chaplets of the conidia-cellules_. This is represented in the accompanying sketches (Fig. 21), which we have purposely contrasted with two similar ones which relate to the _mucor_, of which we shall soon speak. The _conidia_ of these latter are very remarkable, and their fermentative character becomes apparent as soon as their growths are deprived of air. [Illustration: Fig. 21 A. Growth with abundant air-supply at the edge of the mycelium crust.] [Illustration: Fig. 21 B. Growth with reduced air-supply in the central and deeper parts of the mycelium.] [Illustration: Fig. 21 C. Growth with abundant air-supply at the edge of the mycelium tuft.] [Illustration: Fig. 21 D. Growth with reduced air-supply in the central and deeper parts.] It is scarcely necessary to add that in these vegetations of aspergillus, which were accompanied by a corresponding alcoholic fermentation, it was impossible to find cells of yeast; and that, notwithstanding this, the liquid was so adapted to ordinary alcoholic fermentation, that, when we added a small quantity of yeast to it, in the course of a few hours, a most active alcoholic fermentation declared itself. We may give some other facts relating to a crop of _aspergillus glaucus_ which was also grown in ordinary hopped wort, and which was left to itself for a year. A two-necked flask, holding 300 c.c. (rather more than 10 fl. oz.) was prepared and impregnated on December 21st, 1873, and was then placed in an oven at a temperature of 25° C. (77° F.). The fungoid growth developed in isolated tufts, which subsequently united, but without entirely covering the surface of the wort. A few tufts also vegetated at the bottom of the liquid; those on the surface soon became surrounded by large bubbles of gas.