68o 



Reading-Course for Farmers' Wives. 



decomposition of animal and vegetable substances. These little organ- 

 isms are a low order of plant life, and are known as bacteria, molds and 

 yeasts. They have different effects under different conditions. Every 

 housekeeper is familiar with yeast and molds. When molds are growing 

 they are visible to the naked eye, as for example, when they form on 

 cold potatoes, bread, cake, fruit, preserves, etc. One can easily see 

 the results of the action of yeast when it is used to raise the bread, 

 but it is necessary to have a microscope to see the growth of the plant; 



Fig. 177. — .4 convenient 

 preserving kettle. 



Fig. 178. — A sieve tc keep hack 

 the seeds. 



this action is beneficial to the dough. It is also possible to note the 

 action of bacteria on, various substances and in foods. To see the little 

 organisms themselves a very strong microscope is necessary. These 

 organisms are sometimes called microbes. The bacteria, yeasts, and 

 molds, as well as their spores, are usually in the air, in the soil, in water, 

 and on all animal and vegetable substances. Some of the features of 

 these minute plants have been explained in earlier Bulletins of the 



Fig. 179. — A colander for all 

 sorts of straining. 



Fig. I So. — Extension strainer, convenient to 

 place over kettle. 



Farmers' A\'ives' Reading-Course, but it will be well to review them 

 in relation to their bearing on canning and preserving of fruits. 



Some Characteristics of Yeast. 



For growth the yeast plant requires moisture, warmth, oxygen and 

 sugar. The temperature most favorable is between 80 and 90 degrees, 

 Fahr. 



The method of growth is what is known as budding. Wdien the 

 yeast plant finds itself where conditions of temperature, moisture and 

 food are favorable, it begins to grow. A little plant starts from the 

 side of the growing plant, and soon is about as large as the parent. 



