Pasteur's engraving to illustrate the diseases found in fermenting beer. It is taken from the London edition (1789) of Studies on Fermentation, by Louis Pasteur. The illustraton is divided into seven sections. 1) The ferments of turned" beer; the globs are yeast & the disease ferment is the slender filaments. 2) Lactic ferments of beer; yeast & "small fine ferments, contracted in their middle" (lactobacilli). 3) Ferments of putrid beer; motile filaments. 4) Ferments of ropey beer; yeast cells & strings of cocci. 5) Ferments of sour beer, named by Pasteur, Mycoderma aceti. 6) A normal percipitate for comparison. 7) Another coccus giving the beer a "detestable" flavour."