GEEMS. 19 



(cells or germs) which only required the nitrogen of 

 the air or the salts to enable them to multiply" (Dar- 

 win's theory). 



Dr. Osier also says : "The study of the life of these 

 diminutive plants (germs) excites the wonder of those 

 who make observations upon them. It is truly marvel- 

 ous to know r that these bacteria can accomplish in their 

 short lives of possibly a few hours or days, feats which 

 would baffle the cleverest of chemists if given years of 

 a lifetime to work upon. 



"They give to the farmer the good quality of his 

 crops, to the dairyman superior butter and cheese; they 

 assist in a large measure in freeing our rivers and lakes 

 of harmful pollution/' 



In bread baking the same changes take place as that 

 described in the growth of the seed. Flour consists 

 mostly of gluten and starch, with a little water and 

 sugar. In making bread, yeast is generally added, and 

 this takes the place of the diastase in the seed. Yeast 

 converts the sugar into alcohol, carbonic acid gas and 

 water. It also acts upon the starch and converts some 

 of it into sugar, so that the per cent of sugar remains 

 about the same. There is a loss of about five per cent 

 of starch. When milk emptyings are used, there is 

 first a mixture of milk and flour; this kept at blood 

 heat rapidly develops yeast and the result is the same. 

 In baking bread the alcohol and some of the water 

 evaporate, and the carbonic acid gas in its efforts to 

 escape lifts or raises the tenacious dough, and thus the 

 bread becomes light. Bread that is well baked still 

 contains forty-five per cent of water. 



