In a previous communication1 it was shown that Trichophyton gypseum was capable of producing a more alkaline pH in Sabouraud's bouillon when grown on a medium with an initial pH of 4.0 to 8.0. At an initial pH of 9.0 to 10.0 the organism acidified the medium. There was occasionally acidification in buffered solutions which had an initial pH of 7.0. At the end of variable periods of growth, approximately seventy-five to eighty days, the hydrogen ion concentration would finally become stabilized at a pH of 8.3 to 8.6.
We were able to demonstrate in experiments embodied in a recent paper2 that the component of trichophytin capable of eliciting a positive reaction to a cutaneous test was found in the bouillon itself as well as in the pellicle of a culture in Sabouraud's bouillon.
A number of observers have maintained that this skin-reactive