Aspergillus oryzæ, Ahlburg.—The growth is at first yellow or yellowish-green and later brown. The conidia are either smooth or slightly warted, and are 6 to 7 μ in diameter. Perithecia have not yet been found; under certain unknown conditions sclerotia are formed (Schiönning and the author). The optimum temperature for the growth lies above 30° C. It forms both maltase and diastase.

The species plays an important part in East Asia, where it is employed on account of its powerful diastatic action in the manufacture of saké. Saké, or rice beer, has been the national drink of the Japanese for thousands of years. Its preparation is carried out in the four following stages: (1) Preparation of "koji"; (2) preparation of "moto"; (3) the true fermentation; and (4) pressing and clearing. The whole process lasts from November till February. It is begun by the above fungus transforming the rice starch into sugar by its diastatic action; the sugar is then fermented by one or more alcoholic yeasts either taken from the air or accidentally present in the material. It is thus an impure fermentation. Koji" consists of rice grains which are grown over and penetrated by the mycelium of the fungus. It is prepared by sowing the conidia of the fungus, a yellow-green powder, "tane-koji," on steamed rice, the former then being allowed to germinate at 20° to 25° C. One vol. of conidia is said to turn about 40,000 vol. of rice into koji. The process is completed in the course of a few days. "Moto" is made by mixing steamed rice with water and koji to form a thick soup. After some days the whole mass begins to liquefy, the diastase of the fungus turning the starch into a solution of sugar. During this process the temperature is only a little above 0°. Fermentation then begins of itself, whereupon the temperature is raised to about 20o C., and later to 30°-35° C. After fourteen days the moto" is ready; it is a liquid containing sugar, alcohol and lactic acid and particularly yeast cells which are used in the true saké fermentation. For the latter a large quantity of steamed rice, koji, moto and water is mixed up, and the whole is stirred up into a soup, placed in a fermenting vat and left to itself. The process finishes in two weeks. The fermented liquid is then pressed out. In the year 1888-89, 7-2 million hectolitres (44 million barrels), of saké were manufactured in Japan; from this the extensive use of the fungus may be seen.

Aspergillus fumigatus, Fresenius, has conidia which are at first bluish-green and later brown. According to Cohn it is the cause of germinating barley, which has not been properly turned, becoming warm. This species causes diseases in the air passages of mammals and birds.

Aspergillus niger, van Tieghem, belongs to the sub-genus

Sterigmatocystis, its sterigmata being branched. The colour of the growth is black. The conidia measure 35 to 45 μ in diameter, and are furnished with small warts. It forms spherical or cylindrical brownish-yellow or reddish-brown sclerotia, which are 0.5 to 15 mm. in diameter.

The fungus contains diastase, maltase, invertase and emulsin, and, according to van Tieghem, breaks up tannin into gallic acid and glucose. Wehmer states that it is one of the most active producers of oxalic acid, turning half of the sugar exposed to it into oxalic acid. It is not always capable of doing this, however; perhaps in this there are two similar species concerned. It belongs, like the preceding one, to the pathogenic species.

2. Genus: Penicillium, Link.

The conidiophore has septa and has short branches near the top. On the latter, as well as on the main axis, are formed flask-shaped sterigmata, on which are chains of conidia (Fig. 108 A). Sometimes the conidiophores are fasciculated; this form of development was formerly classed in a separate genus, which was called Coremium. Ascus fructification has been observed only in a very few species; it was found by Brefeld in P. glaucum and by Zukal in P. luteum, and is a somewhat rare occurrence in these two species. But it is said by Ray to occur frequently in P. sacchari. The conditions of its formation are not known with exactness, and it is thus always a matter of uncertainty whether this fructification will be obtained.

Wortmann found living Penicillium conidia in wines. which were many years old and contained a high percentage of alcohol; their resisting power thus seems under these circumstances to be very great.

Penicillium glaucum, Link (Figs. 107 and 108) (P. crustaceum), is a collective species under which are grouped a

large number of forms which differ only slightly, and which can scarcely be distinguished from one another by means of the characteristics at present at our disposal. The colour of the growth, initially white, then bluish-green, later grayishgreen, and finally often grayish-brown, is common to all. The conidia are spherical, and 2:5 to 4 μ in diameter.

FIG. 107.-Penicillium glaucum, Link. a, The conidium originally seeded. b, Mycelium. c, Conidiophores. 120. (After Brefeld.)

The ascus fructification discovered by Brefeld proceeds, according to him, in the following way: A yellow or brown sclerotium is first formed, 1 to 15 mm. in diameter; this is produced by a screw-shaped ascogonium developing on a mycelium thread and being surrounded by a growth con

sisting of branched mycelium threads, which grow up partly from the base of the ascogonium and partly from the mycelium. This growth becomes gradually denser and harder; the ascogonium enlarges and its branches force themselves in all directions between the middle growth, consisting of thinner-walled cells. When such a sclerotium, fully ripe, is placed on damp filter paper, the ascogenous threads separate and push out thick side branches, the links of which finally change into asci. At the same time thin threads develop from the ascogenous hyphae which penetrate into the sterile growth and dissolve it up. The foodstuffs thus

FIG. 108.-Penicillium glaucum, Link. A, Conidiophore. B, Sexual organs. C, Beginning of sclerotium (a, ascogenous hyphæ; b, sterile threads). D, Very young sclerotium in section.

obtained are taken by the fine threads to the ascogenous hyphae. Finally, the dissolving process progresses so far that only the peripheral rind remains, while the inside appears filled up with spore masses. Perithecium formation takes place, according to Brefeld, only by abundant nourishment on bread. The ascospores, eight in each ascus, are yellowish, elliptical, 5 to 9 μ long and 4 to 7 μ broad.

The cardinal temperatures for the growth vary, according to Thiele, with the substratum. Thus the fungus is said to grow at 35° to 36° C. if glycerine and sodium formate

are present, whereas 4 per cent. of grape sugar impedes growth at a temperature above 31° C. The temperature minimum is, on the contrary, unchanged by the substances named.

Pasteur states that the conidia are killed if exposed for half an hour to a temperature of 127° to 132° C.; at 119° to 121° C. they retain life. According to Lesage they are killed somewhat quickly by alcohol vapour, the times being six days, nearly one day, and two hours when subjected to the vapour from 22.5 per cent., 45 per cent., and 90 per cent. solutions of alcohol respectively.

P. glaucum contains diastase and maltase (Bourquelot), also a ferment which inverts cane sugar, and emulsin (Gérard). The diastatic action is, however, weakened if the content of the substratum in sugar increases; in a 10 to 15 per cent. cane sugar solution this fungus forms no diastase (Katz). It, further, breaks up tannin into gallic acid and glucose (v. Tieghem) and mandelic acid into its two optically active isomers, using the levo-acid in building up the cells (Lewkowitsch); this is said by Pfeffer, however, to be dependent for the most part on external influences. Under certain conditions it is said to be capable of forming mannite as the product of decomposition (Muntz). Rotten grapes with Penicillium growth may therefore produce a sick wine containing mannite. Calcium oxalate is deposited in the perithecia.

Mention of its occurrence on barley and malt, and its injurious action on wort and beer is to be found on p. 273.

When it is present in grape must, fermentation is much delayed. Müller-Thurgau is of the opinion that the cause of this is the formation of injurious substances, for fermentation is also restrained when the fungus is removed from the liquor before the addition of the yeast. Miyoshi found that it forms a specific protoplasm poison, and J. Behrens has shown experimentally its poisonous action on yeast as regards both