294 SUMMARY OF CURRENT RESEARCHES RELATINQ TO 



ditions of a large number of diflfereut fungi of higher organization 

 belonging to the class of moulds ; and reaffirms the position pre- 

 viously taken up by himself that the various forms of Saccharomyces 

 constitute a distinct and independent group, having its nearest affinity 

 with the lower Ascomycetes. The present state of the question he 

 expresses thus : — That process of development which is termed, where 

 occurring typically in the yeast-fungi, " torulose budding " (hefeartige 

 Sprossung), takes place in a large number of higher and lower 

 genera of fungi often but little related to one another. All these 

 genera pc^sess, besides this mode of propagation, also other, usually 

 filiform, organs of vegetation, and are distinguished by their special 

 mode of propagation for each tyi)e. The ferment-fungi distinguished 

 as Saccharomyces possess, on the other hand, no other organs of 

 vegetative projjagation than the bud-cells [Sprossungszellen) ; and as 

 specific organs of reproduction a peculiar mode of spore-formation 

 which is not found in any of the other forms of fungus named. 

 Saccharomyces has as little to do with the higher fungi which, under 

 certain conditions, may propagate in the same way, as a filamentous 

 alga with the protonema of a moss. All the evidence we have at 

 present goes to show that Saccharomyces must be regai'ded as a 

 degraded ally of Exoascus. 



Systematic Independence and Position of Saccharomyces.* — 

 C. Fisch also contests Brefeld's views, and on the same grounds as 

 Reess. He describes a new species of Ascomyces (a subgenus of 

 Exoascus), under the name A. endogeniis, parasitic on the alder, and 

 in the epidermal cells, not between these and the cuticle, in which 

 each spore is identical in structure with a Saccharomyces-cell, thus 

 confirming the conclusions of Eeess f as to the affinities of the latter. 

 The mode of spore-formation in Saccharomyces is that of an ascus, as 

 in the lower Ascomycetes, not of a sporangium, as in Mucor. 



Influence of External Conditions on the Development of Myco- 

 derma vini.| — S. Winogradsky has carried out a series of experi- 

 ments to determine the action of external influences on the develop- 

 ment of the lower fungi, and also to solve the question how far the 

 form of the cell remains constant under varying conditions of nutri- 

 ment. For this purpose he made use of Geissler's chambers, connected 

 with two glass vessels by caoutchouc-tubes. The culture of Myco- 

 derma was all derived from the same mother-cell. In one series of 

 experiments the organic constituents of the nutrient fluid were changed, 

 while the mineral constituents remained constant ; in the other series 

 variation occurred only in the latter. 



The general result of the first series of experiments was that when 

 the supply of oxygen was abundant, the Mycoderma grew by means 

 of ordinary budding, while, under deficiency of oxygen, the growth 

 partook of a mycelial character. As regards the mineral constituents, 



* Biol. Centralbl., iv. (1884) pp. 484-8. 

 t Supra, p. 293. 



i Arbeit St. Petersb. Naturf. Gesell., xiv. a884) pp. 132-5 (Russian). See 

 Bot. Centralbl., xx. (1884) p. 165. 



