FORMATION OF FAT IN FUNGI. 385 



phosphoric acid. Now if merely a trace of spores or of P'ungus is sown in the 

 solution, an increase of the Fungus, and thus of fat, to the extent of more than 

 a millionfold is obtained. The proteid may be replaced by Asparagin or Leucin 

 with a hke result. Moreover, sugar and ammonia or ammonic tartrate, with the 

 addition of ash- constituents, suffice for nutrition. Instead of sugar, mannite 

 or glycerine, and instead of tartaric acid, acetic or salicylic acid or some other 

 organic acid may be used. In most cases, again, ammonia may be replaced by 

 nitric acid as the source of nitrogen. ' If, instead of ammonia or nitric acid, 

 albumin or peptones are employed as nutriment, the production of fats and 

 cellulose from sugar or tartaric acid etc. is demonstrated, when only a little of the 

 former, but a large quantity of the non-nitrogenous compound is present in 

 the solution. The analysis of the crop in this case shows that only the albuminate 

 can be derived from the proteid of the nutritive solution, and that the whole, or at 

 least a great part of the fat and cellulose must be derived from the constituents of the 

 sugar or tartaric acid. The facts alleged undoubtedly prove that the Fungus cells 

 can take the material for the formation of fats from the most various nitrogenous 

 and non-nitrogenous compounds.' Moreover, the theoretical chemical explanation ot 

 these processes is rendered more difficult by the fact that the chemical constitution 

 of the nutritive solution appears to be, as Naegeli says, almost without significance 

 for the formation of fat in the Fungi. 



Concerning the relation of the formation of fat to respiration, Naegeli remarks : 

 ' The Mould-fungi only grow when they have access of free oxygen, and abound in fat : 

 Beer-yeast requires very little oxygen for its development and is deficient in fat, and 

 the same is true of the Schizomycetes {Bacterid). The Mould-fungi living on the 

 surface of the nutritive fluid contain more fat than their own submerged budding 

 forms. Free access of air is necessary for the formation of spores which contain 

 much fat. The Saccharoniycetes (Yeast-fungi), as is well known, only develope 

 spores when they are spread out on a substratum and lie in a half dry condition : the 

 Schizomycetes likewise, as it seems, never produce their spores in the liquid, but 

 only in the covering at the surface. Mould-fungi living in liquids only form resting 

 > spores abounding in fat on the hyphse which rise up into the air. Why the Fungi 

 thus require oxygen for the production of fat, however, remains in the meantime an 

 open question.' 



These details as to the formation of fat in the Fungi, which may probably be 

 '. extended in essential points to more highly developed forms also, are the more 

 interesting since the Fungi collectively and individually produce no starch, and even 

 form true sugars only in small quantity or not at all, though mannite, on the other 

 hand, often occurs in them. Even the cellulose of the Fungi is in some respects 

 different from that of other plants, not giving the usual blue coloration with iodine 

 and sulphuric acid. 



It has already been remarked that Yeast and the Bacteria, besides many other 

 Fungi, not only use up the surrounding substratum to extract from it the constitueivts 

 of their own nourishment, but that they cause fermentation and putrefaction at the 

 same time, i.e. decompose the complex molecules of the carbo-hydrates and proteid 

 substances, and this in far greater quantity than is in any way necessary for the 

 purposes of their own nourishment. This ferment-action is peculiarly energetic in 



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