396 BACTERIOLOGICAL CHEMISTRY 



were shown to contain the reduction products. 4 ; 5- 

 dihydroxy-7-methoxy-2-methyl-9-anthranol and the 

 corresponding 10-anthranol in addition to the oxidised 

 form, physcion. Instead of the usual polyhydroxy- 

 anthraquinones, H. leersii gave two reduced compounds, 

 luteoleersin, C26H38O7, yellow rods, and colourless, albo- 

 leersin, C26H40O7, which are regarded as the semi-quinone 

 and quinol respectively and which can easily be converted 

 into one another by oxidation-reduction processes. 



Fairly closely related to the anthraquinone pigments 

 are the yelloAv pigment ravenelin, 1:4: 8-trihydroxy-3- 



HO CO OH 



met hylxant hone, > which is 



\ /\ /\ /^^' 

 \/ \/ \/ 

 O OH 



produced by H. rave^ielii and H. turcicum, and rubrofus- 

 arin, C15H12O5, red crystals, which is a dihydroxy- 

 methoxy-methylxanthone produced by Fusarium 

 culmorum. 



The yellow crystalline pigment of the mycelium of 

 Oospora sulphur ea-ochracea, sulochrin, 



COOCH3 OH 



^\ II /\ 



II c 1 I 



HO I jloCHa HO I 'cHa 



is a benzophenone which is related to ravenelin. 



A number of other mould pigments are known but 

 their constitution is unknown for the most part. The 

 structure of citromycetin, the yellow pigment from P. 

 citromyces-glabriim, is partially known : — 



