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deleterious influence on the growth. It is a form of yeast, and ferments maltose, dextrose, saccharose and 2 dextrin ; it contains invertin. This fungus is employees advantage in South American distilleries. as it is able : stand the warm climate.
Schizosaccharomyces octosporus, Beijerinck (Figs. 104 and 105), was found by Beijerinck on currants free Greece, and by Schionning on Italian raisins. Some of str cells are cylindrical, some oval, and in fresh wort cultur they are 4:5 to 6 y broad and 7 to 13 x long.
The remarkable ascus formation in this species (Fig. 86) observed by Schiönning is described on page 211. The number of spores is eight as a rule, but somewhat frequently only four are found; the number may also vary from two to seven. The shape of the ascus varies; so also does its size ; the breadth is 6 to 10:5 y, and length 14 to 20:5 The size of the spores is 3 to 5 H. The latter are stained blue with a solution of iodine in potassium iodide (Lindner). They are formed copiously on solid nutrient substrata, more scantily on gypsum blocks and in wort cultures.
ording to Seiter they are formed on gypsum blocks at
in six to seven hours. This species develops no film on rt, but at room temperature a weak yeast ring is formed a month.
It ferments maltose and dextrose, but not saccharose. shiönning states that this fungus forms in beer wort bout 14 per cent. Ball.) 4:6 vol. per cent. of alcohol in iree weeks. at 25° C., and 6:56 vol. per cent. of alcohol in ive months.
Fig. 105.---Schizosaccharomyces octosporus, Beijerinek. A young growth on wort
gelatine ; some cells contain spores. 1999. (After Schiönning.)
Schizosaccharomyces mellacei, Jörgensen, was isolated by Greg from Jamaica rum. The spores of this species are stained blue by iodine in potassium iodide (Holm). Altogether Greg is said to have found eight species of Schizosaccharomyces in the mashes in rum manufacture.
Order 11.-Perisporacea. The asci are enclosed in the so-called perithecium; the latter is an envelope more or less spherical, completely closed, and consisting of one or several layers of cells (Fig. 106 6).
The conditions governing the formation of these perithecia have been studied by Hansen and Klebs. Hansen made most of his experiments with Anixiopsis stercoraria, Hansen, a fungus which grows in the open air on manure, and which also thrives in wort and on wort gelatine. He found that in cultures on wort gelatine and wort agar gelatine the limits for mycelium formation lie in the neighbourhood of 36° C, and 2° C. At 25° C. a vigorous formation of perithecia takes place, but it is over long before 35° C. is reached, and its minimum limit is near 8° C. It is thus seen that the temperature maximum for the development of the mycelium and gemmæ lies remarkably higher than for the development of perithecia, and also that the development of mycelia and gemmæ has a lower minimum temperature than the development of perithecia. Therefore, growths may be prepared, according to wish, with or without perithecia. This behaviour is exactly the same as he observed in the saccharomycetes as described already (p. 210), namely, that the budding of yeast still proceeds at temperatures which, on the one hand are higher, on the other are lower, than those at which spore formation can take place. He puts this down as a general rule for most fungi.
Klebs found that perithecium formation can always be brought about with absolute certainty in Aspergillus repens, de Bary, on new bread between 25° and 32° C. Below 25° C. the result becomes uncertain; between 12o and 22° C. no fructification is in general observed. On cultivating this species on 80 per cent. dextrin he further found that only conidiophores are developed if the cultivation takes place at 16°, but that if a temperature of 28° C. is employed, the growth consists almost entirely of perithecia. At 15° C. formation of perithecia also takes
place, but only if the formation of conidia is in some way restricted.
Vegetative increase occurs in many of the allied forms by means of conidia. Several species form sclerotia. This term is applied to certain hard tubercular bodies which have a rind, and are often dark coloured. They consist of a thick web of mycelium threads, and serve for storing reserve food stuffs. After a period of rest, the length of which varies, they germinate into fruit carriers or fruit bodies.
The Perisporaceæ are, with the following order, the Sphæriaceæ, divisions of the Pyrenomycetes.
Several Aspergillus and Penicillium species cause much damage in breweries by attacking the barley and malt, particularly the broken grains. J. Rauscher has carried out comparative experiments with wort from mouldy and nonmouldy malt and Lott later obtained the same results, viz. : (1) that mouldy malt gives less extract than normal malt;(2) the ratio between sugar and non-sugar diminishes ; (3) the quantity of fermentable material decreases so that beer prepared from mouldy malt contains less alcohol ; (4) the quantity of acid in the wort increases. On the other hand he found, in contradiction to previous observers, that the malt attacked by the mould does not cause a mouldy smell or taste in the wort nor in the beer prepared with it. Prior mentions that beer can of itself assume a mouldy taste, if it is merely lying in a mouldy cellar.
In laboratories these fungi may be kept, either in the dry state in filter paper, or in a 10 per cent. saccharose solution. In both cases they live for a great number of years. In the case of Aspergillus glaucus, Hansen found that this species kept alive in a paper preparation for more than sixteen years, and Anixiopsis stercoraria lived, under the same conditions, for more than twenty-two years.
1 MOULDS (ASPERGILLEE). On theo phores are flask-shaped bodies, sterigmata or basidia, from which the conidia are formed by abstriction (Figs. 106 1, 2, 107 and 108 A).
1. Genus : Aspergillus, Micheli. The end of the conidiophore is inflated into a head. On this head the numerous small flask-shaped sterigmata are found from which the conidia are either directly detached, or the former all bear several smaller sterigmata from which the conidia are developed. Those species, in which the latter form of development takes place, are often classified in a genus by themselves : Sterigmatocystis, van Tieghem. Species are found, however, which exhibit both forms.
Ascus fructification (Figs. 106 5, 6) is known only in a few species which were formerly reckoned in the genus Eurotium, and we really ought therefore to class only these species with the ascomycetes till something further is known, while the others would be placed among the Fungi imperfecti. It was first demonstrated by de Bary that Aspergillus is the conidial stage of Eurotium. In some species a formation of sclerotia takes place without any appearance of asci, and in single forms gemma formation is said to appear under certain conditions of culture. Contrary to the following genus, Penicillium, in which growth goes on at very low temperatures, e.g., near 0°, the aspergillæ favour higher temperatures.
Aspergillus glaucus, de Bary (Figs. 106 6-8), is a general designation for several species among which A. repens, de Bary (Fig. 107 1-5), may be mentioned specially. The growth forms on the substratum a covering at first bluishgreen and later brownish. The conidia are 6 to 15 u in