This first epoch stands in close relation with the general abounding strength of that period of civilization. Adventurous sailors and explorers had broken the bonds of the known earth, plain men had dared to enter the lists with that hierarchy, to attack which had been held profanation; art had thrown aside the old traditions and brought out the old master-works, the world of scholars had torn itself loose from petrified scholasticism and turned to the ancient classics, and, as in most branches of science, so also in chemistry, there was a genuine revolution, and it was studied in reference to medicine almost as assiduously as it had previously been in the search for the philosopher’s stone. New inquiries were set on foot, old problems revived and attacked from a new point of view, and among these the subjects of yeast and fermentation played an important part. Not many decades have passed since the practical brewer found neither interest nor profit in theories of fermentation, and especially all chemical and physical discussion of his work and processes. The purely scientific style which too often had very little reference to the practical man, and the various contradictory views and learned controversies were not calculated to attract the interest of the beer brewer. Scholars discussed and disputed, the man of trade brewed and coopered, and neither paid any attention to the other. Now the case is very different. Intelligent and thoughtful brewers have been forced to admit that an insight into the nature of the materials they use, and the changes these undergo while in their hands will not merely enlarge their intellectual horizon, but be of great practical use in their business, and in consequence are found keenly alive to the progress of scientific inquiry.