374 CHEMICAL ANALYSIS OF ASPERGILLACE^. 



connection, reference may be made to PFEFFER'S (II.) reports on 

 the selective affinity for nutrient substances (see vol. i. p. 46). 



With regard to oxalic acid the decomposition of which is 

 mentioned in certain older reports by WARBURG (I.) in the case 

 of " Penic. glaucum" by DUCLAUX (XXI.), Werner and others 

 more accurate researches by WEHMER (XXVI., XXVII. and V.) 

 have shown that i per cent, solutions are not attacked by these 

 two organisms, whereas 0.2-0.5 P er cent, solutions are com- 

 pletely, though slowly, decomposed. Soluble oxalates are decom- 

 posed with greater difficulty and in the case of Aspergillus only 

 under certain conditions though with even a small growth of 

 Penicillium, 1.5 grms. of potassium oxalate have been completely 

 eliminated in sixty days. In all experiments of this kind, how- 

 ever, the nature of the food-stuff and the temperature require to 

 be taken into consideration. It may be remarked, in conclusion, 

 that Asp. oryzce is credited by Aso (I.) with secreing an oxy- 

 dase, whilst Pozzi-EscoT (I.) states that the same fungus pro- 

 duces a reducing enzyme, which he calls " Jacquemase." Extracts 

 of the vegetative growths of all the species examined by SCHAFFER 

 (IV.) see p. 365, vol. ii. failed to give with acidified guaiacol 

 solution the orange precipitate stated by BOURQUELOT (IX.) to be 

 characteristic for oxidising enzymes. Seven species, however, 

 gave a positive reaction with guaiacol and hydrogen peroxide, 

 among them being "Penic. glaucum," which, according to GRUSS 

 (I.), has no oxidising action. SAITO (IV.) claims that Asp. oryzce 

 secretes catalase; and, according to ALTENBURG (I.), Asp. niger 

 secretes an oxydase which liberates iodine from potassium iodide 

 and was more closely examined by RACIBORSKI (III.). 



