fermentation and fermentative power. By a stronger nutrition of the yeast, e.g., by addition of peptone to the nutrient solution, he succeeded in stopping this injurious action. The fungus causes the mouldy taste in wine, as well as a cork or stopper taste, by growing through the cork of the bottle (Wortmann). Like Aspergillus, it attacks hops, colouring them brown.

P. glaucum is very widespread in nature, and the air is full of its conidia. It is, therefore, one of the most dangerous guests in the laboratory, all the more as it only requires a very small quantity of nutriment for the support of life; but it also requires a certain amount of moisture. With regard to temperature, too, it is not particular; it thrives well at about 0°. It is frequently met with on fruit, kernel as well as stone fruit, and it is said to be able to penetrate the uninjured surface of grapes. Wehmer found it in herring pickle, and isolated it by means of plate cultures on nutrient gelatine, containing 10 per cent. of common salt, on which substratum it grew easily.

It betrays its presence by its characteristic smell.

Order III.-Sphæriacea.

The fungi belonging to this order have, with one exception and contrary to the Perisporacea, an opening in the dark-coloured perithecium. Conidia fructification takes This order includes a very large number of parasitical species.

place.

SPHERIEÆ.

Genus: Sphaerella, Cés. and de Not.

The almost spherical perithecia are set in the epidermis or in the uppermost layers of the web of the host and end in a simple, uncommon, papilla-shaped opening of fine skin-like consistency. The asci are connected in bundles; the spores are two-celled and colourless (seldom coloured).

Sphærella Tulasnei, Janczewski (Fig. 109), forms darkcoloured perithecia, frequently pear-shaped (Fig. 1097), 0:3 to 04 mm. long and 0·15 to 0.20 mm. in diameter. At its surface, chiefly at the neck, numerous mycelium threads are often found which develop conidiophores (Fig. 109 7). The perithecia contain asci with eight spores (Fig. 109 8, 9), of which the topmost is larger than the others; its size is 28 μ in length and 6.5 μ in diameter.

The conidial form is one of those fungi which were formerly called Cladosporium herbarum, Link (Fig. 109 1, 2, 3). This name has been used, like Penicillium glaucum, Aspergillus glaucus and others, to designate several fungi. It is now impossible to say which species Link meant. Common to all is the mycelium, at first clear like water, and later olive green or brown, which sends out conidiophores that abstrict brown conidia often many-celled. The form named Cladosporium herbarum by Janczewski corresponds with that usually so called (Fig. 109 1-4). He describes the conidia as oval, either undivided or 2 to 5 celled (Fig. 109 5). In the largest varieties they are 25 μ long and 10 μ broad; in the smaller forms they are only half as large. Their cell wall is olive brown, often warty, but smooth in the smaller variety. The young mycelium is uncoloured, and only assumes the olive brown colour gradually. For the rest, the appearance may be made out from Fig. 109.

Janczewski showed, by experiments with seedings on barley and rye, that this fungus is the conidial form of the above Sphærella Tulasnei. It grows here as a saprophyte, not as a parasite. As soon as the conidia were brought to germination on nutrient gelatine, a piece of the gelatine with germinating conidia was placed on a cut rye leaf which was kept in a very damp atmosphere. The mycelium then grew up; as soon as the point of the latter reached one of the stomata in the leaf, it forced its way through this into the leaf,

2.

3

6.

FIG. 109.-Sphaerella Tulasnei, Janczewski. 1, 2, 3. The conidial form Cladosporium herbarum, Link. 250. 4. The same growing out through a stoma in the rye leaf sheath. 3. 5. Conidia. 5. 6. Sclerotium with a mycelium thread in a rye leaf sheath. 49. 7. Perithecia with conidiophores. $. 8. Longitudinal section of perithecium containing two asci with endospores. aga. 9. Ascus with ripe endospores. 400. 10. Conidiophores developed from endospores. 32. ( After Janczewski.)

here it continued to grow. When the seeding was done winter (and only when done during the latter season), he mycelium often developed sclerotium-like bodies (Fig. 09 6), which were then transformed into perithecia. anczewski never found these bodies in nature on the eaves of any kind of corn. Placed on nutrient gelatine they were covered by mycelium threads extending radially and often in large quantity. After a few days this mycelium formed conidia. The transformation of sclerotia into perithecia takes place quickly. The ascospores germinate easily on nutrient gelatine, and, in a few days, develop mycelia with the conidial form Cladosporium herbarum; at the same time certain peculiar organs (Fig. 109 10) appear, the function of which is not known, and which are often found in the immediate neighbourhood of the conidiophores.

Cladosporium herbarum is very common on both dead and living plants. In breweries this fungus appears sometimes in large quantity on the walls of cellars; it is also found on malt, hops, etc. Like some other mould fungi it can give a cork taste to wine (Wortmann). It is not defined yet in how far it is identical with Hormodendron cladosporioides (Fres.) Sacc., yet both fungi are extremely like one another and the latter is probably often called Cladosporium. Janczewski says that he never succeeded in transforming Cladosporium into Hormodendron; but the mycelium developed on the above sclerotia sometimes exhibited a development of conidiophores similar to those of Hormodendron. Another similar fungus is Fumago, very thoroughly studied by Zopf, which is specially to be recommended to those who intend taking up this question.

Order IV.-Discomycetes.

The ascophores are open and have a very varied appearance; they may be either cup, disc, mussel or hat shaped.

The asci generally contain 8 spores, but some species have 16, 32, 64, 128 and sometimes more. In many, conidia fructification is found in addition, and in some, sclerotium formation.

CUP FUNGI (PEZIZACEÆ).

1. Genus: Sclerotinia, Fuckel.

The mycelium produces sclerotia from which stipitate ascophores grow under certain conditions. Conidia fructi

fication takes place.

Sclerotinia Fuckeliana, de Bary (Figs. 110 and 111). This species is best known as the conidia fructification under the name Botrytis cinerea, Persoon (B. vulgaris, Fr.). This fructification is usually developed first on the mycelium. The conidiophores, 1 to 2 mm. long, are branched at the top like panicles; the ends of the branches have bulbous swellings which bear numerous fine sterigmata which again abstrict large conidia. When the latter are ripe, the side branches bearing them die, so that new branches can then take their place.

On

If the conidia are seeded out in an unfavourable substratum, e.g., in a thin layer of water, they germinate and form a very short germ tube; from the latter or from small flaskshaped carriers small conidia (spermatia) are again abstricted, which, however, cannot be made to germinate. the other hand, if the large conidia are put into a good substratum, a typical mycelium is developed which then forms either the usual large conidiophores or, under certain conditions, black sclerotia, a few millimetres thick. If such a sclerotium is brought into a damp atmosphere immediately after it gets ripe, conidiophores again develop; but, if it is kept at rest for a year at least, the ascophore develops in the shape of long-stalked cup fruits (Fig. 110 p).