The difficultly of the clay litter controversy lies in the lack of objective evidence.
Many salts of the acid are known and, with the exception of those of the alkali metals, they are difficultly soluble in water.
For substances of a difficultly combustible nature he adopted the method in common use to-day, viz.
When slowly crystallized it forms large monoclinic prisms which are readily soluble in water but difficultly soluble in alcohol.
It is difficultly fermented by yeast, but readily by the lactic acid bacillus.