Scientific Lectures. 109 



fully watched. It must be stopped at the rujld point, by putting the 

 bread in tlie oven, and the right point waiJKst le/bre any alcohol was 

 2J>roduced. This recalls the advertisement of a baker in London, 

 many years ago, who had heard for the first time that alcohol is a 

 product of panary fermentation. He advertised that bread leaked by 

 him contained none of the alcohol produced in the ordinary process 

 of fermented bread. He was followed, a few days later, by a rival 

 who announced that he took no pains to remove from his bread the 

 alcohol produced in tlie process of fermentation. (It is to be pre- 

 sumed that these establishments preceded the " United Metropolitan 

 Hot Muffin and Crumpet Baking and Punctual Delivery Company.") 

 The quantity of this important product, though small in the indi- 

 vidual loaf, is, in the aggregate, large. Liel;)ig estimates the annual 

 amount in all Germany at not less than T,500,000 gallons per annum. 



Difficulties of gettijtg good Flour and good Bread. 



You do not need to be reminded that with the philosophy of good 

 yeast bread, however clear before you, the ideal loaf cannot be made 

 without good flour. The proportion of this, unfortunately, is small. 

 The wheat runs the gauntlet from tlie day it is lodged in the ground. 

 If it escapes the birds and is permitted to germinate, the soil may be 

 wanting in nourishment, or the winter frost may snap the tender 

 roots and delay the vegetation in spring, or it may bo deluged with 

 rains or scorched and blanched with continuous sunshine and drought : 

 or preyed upon by the weevil or Hessian fly ; or smitten with rust at 

 the critical instant when its organic activities are at the highest ; or 

 caught by showers in the shock and "grown" in the sheaf ; or not 

 sufficiently dry when it goes to the market; or soured in the granary; 

 or heated in grinding ; or it may become sour, and lumpy, and musty 

 in the barrel. After having escaped all these dangers it is dreadful to 

 think of its being poisoned by putrid yeast, or overtaken by a warm 

 dog-day atmosphere, which is fatal to the best yeast, or forgotten when 

 passing through the critical stages of fermentation and baking. It is 

 not to be wondered that science has been invoked to preserve to us 

 this invaluable grain and conduct it through the changes that are to 

 give us bread. Thenard, Bossingault, Dumas, Payen, Megemouries, 

 and others in France ; Liebig, Knapp, Krocker, Mitscherlich, and 

 others in Germany, and Thompson, Hassall, Pereira, Dauglish, 

 Odling, and others in England, have lent their aid. The best bread 



