This is probably an exaggeration of the properties of the hydrogen sulphid found in the stomach.

There is an account of a man of forty-three, a gross feeder, who was particularly fond of fats and a victim of psoriasis palmaria, who on going to bed one night, after extinguishing the light in the room, was surprised to find himself enveloped in a phosphorescent halo; this continued for several days and recurred after further indiscretions in diet.

It is well known that there are insects and other creatures of the lower animal kingdom which possess the peculiar quality of phosphorescence.
There are numerous cases of spontaneous combustion of the human body reported by the older writers.

Bartholinus mentions an instance after the person had drunk too much wine.

Fouquet mentions a person ignited by lightning.