IV YEAST 115 



taken the earliest practicable opportunity of 

 qualifying that which he was obliged to drink ; 

 and the ghosts of the ancient Egyptians were 

 solaced by pictures of banquets in which the 

 wine-cup passes round, graven on the walls of 

 their tombs. A knowledge of the process of 

 fermentation, therefore, was in all probability 

 possessed by the prehistoric populations of the 

 globe ; and it must have become a matter of great 

 interest even to primaeval wine-bibbers to study 

 the methods by which fermented liquids could 

 be surely manufactured. No doubt it was soon 

 discovered that the most certain, as well as 

 the most expeditious, way of making a sweet juice 

 ferment was to add to it a little of the scum, or 

 lees, of another fermenting juice. And it can 

 hardly be questioned that this singular excitation 

 of fermentation in one fluid, by a sort of infection, 

 or inoculation, of a little ferment taken from some 

 other fluid, together with the strange swelling, 

 foaming, and hissing of the fermented substance, 

 must have always attracted attention from the 

 more thoughtful. Nevertheless, the commence- 

 ment of the scientific analysis of the phenomena 

 dates from a period not earlier than the first half 

 of the seventeenth century. 



At this time, Van Helmont made a first step, 

 by pointing out that the peculiar hissing and 

 bubbling of a fermented liquid is due, not to the 

 evolution of common air (which he, as the inventor 



