Part XII.—On a new methoxy-dihydroxy-toluquinone produced from glucose by species of Penicillium of the P. spinulosum series

Reference to the carbon balance sheets given in Part IV for species ofPenicillium shows that three species ofPenicillium ,diagnosed by Dr. Charles Thom as belonging to theP. spinulosum series, were included in Table I. The only salient feature of the carbon balance sheets of these three species is the large amount of acid, entirely of the non-volatile type, which they produce from glucose. These three species—Ad. 74, Ad. 79 and Ad. 80—show, in addition, a very characteristic colour reaction when grown on a modified Czapek-Dox glucose medium containing twenty times the usual amount of ferrous sulphate given in Part I, p. 7. When the above moulds were grown on this medium at 23° C. it was found that a purple ring first appeared immediately under the mycelium and gradually spread downwards till the whole medium became purple. In later stages of growth a yellow ring was formed below the mycelium and it also spread downwards till the purple colour had almost entirely disappeared. When the slightly yellow medium was exposed to the air, as for instance in filtration of the medium, the liquid was found to assume a much darker tint, almost comparable with the original purple. On addition of ferric chloride solution to the filtered metabolism solution a characteristic deep brown colour was produced. Addition of dilute permanganate solution, in the cold, to the filtered metabolism solution resulted in an immediate reduction of the permanganate, the amount of reduction being roughly proportional to the depth of the purple colour and to the intensity of the ferric chloride reaction.