362 CHEMICAL ACTIVITY OF ASPERGILLACE^E. 



being invariably a collective term for a number of very similar 

 species not more closely identified. 



Asp. niger splits up all the sugars here in question (except milk 

 sugar, which still remains doubtful) before consuming them, and 

 therefore secretes invertase (sucrase), maltase, trehalase, meleci- 

 tase (?) and raffinase. This has been demonstrated by a series of 

 observations, dating from the year 1878, by GAYON (V.), Du- 

 CLAUX (XXII.), FERNBACH (FA Bourquelot, Herissey and GIL- 

 LOT (III.). Bourquelot especially both alone and in collabora- 

 tion with Herissey and Graziani has repeatedly investigated 

 these enzymes, and enriched our knowledge of them. The first 

 report of the inversion of saccharose by the fungus dates from 

 1878, namely, by GAYON (V.) ; and Duclaux has repeatedly 

 treated the question since 1883. According to Fern bach, who 

 detected the enzyme in 1890, and also examined the deterrent 

 influence of light on its action, the formation of invertase is 

 not dependent on the presence of saccharose in the culture liquid. 

 In 1893 it was studied by Bourquelot; and in 1896 this worker, 

 in association with HERISSEY (I.), demonstrated the enzymatic 

 splitting up of the trisaccharide melecitose into dextrose and 

 turanose the latter a disaccharide analogous to maltose, and one 

 that cannot be further modified by the fungus, though it can be 

 by the action of acids. The same worker obtained, in 1893 (also 

 by alcoholic'precipitation), an enzyme (trahalase) capable of hydro- 

 lysing trehalose into two molecules of dextrose, and differing from 

 invertase and maltase though it may be identical with the amylase 

 of E. FISCHER (III.) which acts in the same way. BOURQUELOT 

 finally demonstrated the enzymatic fission of maltose and raffinose 

 (VII.) the latter by means of a separate enzyme and also 

 (VI.) that of the trisaccharide gentianose into dextrose (2 mole- 

 cules) and laevulose, subsequent to the intermediate formation of 

 gentiobiose (capable of subdivision into 2 molecules of dextrose) 

 and laavulose (invertase and emulsin), in part of which researches 

 he collaborated with HERISSEY (III.). With regard to rafiinase, 

 opinions are still divided, some considering its action limited to 

 the splitting up of melibiose (Ban's " melibiase ") into galactose 

 and dextrose, and that the conversion of melitriose into melibiose 

 and dextrose is accomplished by invertase. According to E. 

 Fischer, it is very similar to maltase ; with which melecitase is 

 also probably identical. Furthermore, according to BOURQUE- 

 LOT (V.), gentiobiose and turanose are also capable of being split 

 up by specific enzymes. The action of maltase was also investi- 

 gated by HERISSEY (I.), and that of raffinase by GILLOT (III.), 

 both working with the same fungus. Consequently, a considerable 

 literature exists on the sugar-decomposing enzymes of Asp. niger 

 alone. 



" Penicilllum glaucum " behaves in a very similar way, this 

 fungus having already been found to contain invertase (Duclaux, 



