44 NORMAL HISTOLOGY. 



ter. In form, the torula is spherical or ovoidal. It has the power 



to produce fermentation, thus changing sugar into alcohol and C0 2 . 



C 6 H 12 6 =2C 2 H 5 OH + 2C0 2 . 



Some of the sugar breaks up into glycerine and succinic acid 

 Yeast contains no chlorophyl, and, therefore,, has not the power to de- 

 compose C0 2 . The elements necessary to form its protoplasm, cel- 

 lulose, fat, etc., are carbon, oxygen, hydrogen, nitrogen, sulphur, 

 phosphorus, potassium, magnesium, and calcium. These are ob- 

 tained chiefly from complex substances, which are broken up by 

 its action, and their elements appropriated to form the new com- 

 pounds required for its growth and reproduction. 



Saccharomyces cervisice is used in making bread, the 00^ formed 

 permeating the dough and making it spongy. Several species are 

 used in making beer and other fermented liquors, different flavors 

 being produced by different species. 



Laboratory exercise No. 6. Teast. Place in a test tube, half filled 

 -with water, a small portion of a cake of Fleischman's yeast, and let 

 stand for a few hours in a warm place. Place a drop of the liquid upon 

 the slide; cover and examine with H. P. Look for single cells; then for 

 a large cell with a small one attached; the small cell is a bud. Find 

 a group of cells; this is a colony. Look also for a chain. Irrigate with 

 magenta, and search for protoplasm and a nucleus. 



Upon the freshly cut surface of a potato sow some yeast cells. In a 

 day or so examine some of the growth and search for ascospores. They 

 will appear as rounded masses within the larger cells. Make drawings 

 to illustrate a single cell, a colony, a chain, buds, and ascospores. 



PROTOCOCCTJS. 



Protococcus is a unicellular, chlorophyl-bearing plant which re- 

 produces by normal fission and by endospores. 

 Classification : 



Kingdom Vegetable. 

 Series Cryptogamia. 



Sub-kingdom Thallophy ta . 

 Class Algaa. 



Sub-class. Chlorophyceae. 

 Order Protocaccales. 



Family Protococcaceae. 

 Genus Protococcus. 



Species Protococcus vulgaris. 

 Protococcus pluvialis. 

 Protococcus nivalis. 



