64 STIMULATIVE INFLUENCES. 



(X.) has published an observation on fungi capable of dissolving 

 horny matter (keratin). 



Diastatic enzymas, i.e. such as are capable of converting 

 starch into sugar, are also very often (§ 117) found in Eumyretes. 

 Many species of the latter are specially productive in this 

 respect, and are employed on this account in the fermentation 

 industries ; this is particularly the case with the species of 

 Mucor that will be described in § 240, and the Koji fungus 

 {Aspergillus ory?:ie) dealt with in the last section but one. At 

 present we shall not treat of the technico-mycological side of 

 this faculty, but merely make a remark of a geneial physio- 

 logical character, namely with regard to the dependence of the 

 formation of this enzyme on the external conditions. In this 

 connection W. Pfeffer (V.) and Jul. Katz (I.) examined 

 PeniciUiiuii (jJaucu/n, Aspenjilhis 7iujei; and Bacillus meijatheriu7n, 

 and found that these two Eumycetes produce diastase, even in 

 the absence of starch, provided no adverse influence comes into 

 play. Such an influence has been traced to the presence of 

 various sugars, in the case of Penicillimn t/Iaucuiti, the formation 

 of diastase at medium temperatures ceasing when the (otherwise 

 identical) nutrient media received an addition of either 1.5 per 

 cent, of saccharose, 2 per cent, of grape sugar, or 10 per cent. 

 of galactose. The secretion was also retarded by 5 per cent, of 

 maltose. Enriching the nutrient properties of the medium is 

 succeeded by an increase in the limit of the foregoing additions. 

 In the case of Aspertjillus ni(jer, an addition of even 30 per cent. 

 of saccharose merely restricts the formation of diastase (at 

 31.5° C.) without suppressing it altogether. The amount of 

 diastase secreted per vxnit of time by this fungus was found to 

 be greater (other conditions being equal) in the case of cultiu-es 

 in which provision had been made for the immediate separation 

 of the resulting diastase by additions of tannin. 



Enzymes (lipases — Hanriot (I.)— or steapsines — W. Bieder- 

 MANN (I.)) capable of decomposing fats, are found not only in 

 the pancreas, blood, and other corporeal fluids of all animals 

 hitherto examined, but also in the vegetable kingdom. Their 

 occurrence in Enmijcetes was first detected in the case of 

 Penicilliarii gJaucum, the discovery being made by E. Gerard 

 (II.) and L. Camus (I.). They were then found by the last 

 named (II.) in Aspergillus niger, and by R. H. Biffen (I.) 

 in an unidentified fungus infesting the cocoanut. J. Hanus 

 and A. Stocky (I.) repoi'ted having observed the production of a 

 similar enzyme by a number of mould fungi in the course of 

 their investigations — referred to in a later section — on mouldi- 

 ness in butter. It is not improbable that several vai-ieties of 

 lipases exist in the fungoid kingdom. The faculty of producing 

 such an enzyme is of particular importance when the nutrient 

 medium is rich in fat, e.g. in the case of fungoid parasites 



