186 



arisen from the spores, on whose threads numerous, minute, 

 yellowish bodies were visible ; a section of one, highly magnified, 

 showed a cellular structure similar to that of sclerotia (1. c, 58). 

 I may mention here that sclerotia are merely forms which the 

 mycelia of many fungi assume when in a state of rest, the Ergot 

 of Rye is a well-known example. Brefeld cultivated these 

 sclerotia, and after the lapse of some months he observed cells, of 

 an elongate and tortuous shape, ai'ise in the midst of their 

 substance. These cells continued to increase in dimension 

 apparently at the expense of the surrounding tissue, for eventually 

 hollow spaces were observed in the sclerotia near them. He 

 compares this process with the growth of the embryo in the 

 embryo-sac of flowering plants (1. c, 60, 61). Next there appeared 

 cells of a difi'erent form arising from the elongate cells, which 

 again gave origin to others of a subglobose shape, and in these 

 eight ovate sporidia wei'e gradually produced by free cell-formation. 

 Brefeld considers the subglobose cells as true asci, inasmuch as 

 they are the result of the conjugation of the filaments within the 

 sclerotia. The cells which give origin to the asci he names 

 ascogones. All this time the outer coat of the sclerotia had been 

 groAving harder till a dense rind was formed ; and by absorption 

 of the surrounding tissue the ascogones and asci were set free 

 Avithin this covering : at last the asci were ruptured, and the 

 sporidia floated freely in the hollow sclerotia, where they remained 

 till the outer bark was dissolved. The time from the sowing of 

 the conidia to the maturity of the sporidia was from six to eight 

 months (p. 71). Brefeld gives a figure of the process of 

 conjugation which he observed in the elongate cells described 

 above, similar to what Tulasne and others have witnessed in some 

 species of Peziza, and which may be easily seen in various algoe. 

 (Vancheria and Bulbochoete). To dispel all doubt as to the 

 correctness of his observation, Brefeld placed the sporidia he had 

 obtained from the asci in the juices of fruits carefully filtered ; 

 after from 18 to 24 hours germination commenced by protrusion 



