fee:\iextatiox ORGAJSTISMS 97 



SECTIOX XVI 

 SOME ORGANISMS CAUSING IMPORTANT FERMENTATIONS 



In the preceding sections the activities of bacteria were the 

 chief topic of study. This section will principally treat of the 

 activities of another group of plants, namely, the yeasts and mold 

 fungi. These organisms, though somewhat more complex, resem- 

 ble iQ many ways the bacteria ; they are devoid of chlorophyll, 

 grow upon organic substances, and reproduce rapidly by small 

 spores, which, when liberated, may be carried long distances in 

 the air. They are thus distributed as widely as bacteria. 



The physiological activities of these fungi, on account of their 

 great importance ia the arts and industries, have been extensively 

 studied. It is as producers of fermentation that they are of 

 interest in agricultural and industrial technology. 



In the modern sense the term fermentation is a very broad 

 one. As defined by Lafar, " Fermentation is a decomposition 

 or transformation of substances of various kinds brought about 

 by the vital activity of fungi." In the older and more common 

 use of the term fermentation it designates the formation of 

 alcohol and carbon dioxide from a carbohydrate — for example, 

 the fermentation of wine from must. It is perhaps needless 

 to say that these phenomena were observed and used in the 

 arts centuries before the scientific basis of the process was 

 demonstrated. 



The literature upon fermentation and the organisms which 

 cause it is voluminous. References to a few of the more general 

 treatises are given herewith : 



Lafar. Handbuch d. teohn. Mykologie. Jena, 1905-1908. 



JoRGEssEN. Micro-organisms and fermentation. Transl. by Davies. Philadel- 

 phia, 1901. 



Klocker. Die Garungsorganismen. Stuttgart, 1900. 



Hardex. Alcoholic Fermentation. Xew York, 1911. 



Marshall. Microbiology. Philadelphia, 1911. 



DeBary. Comparative Morphology and Biology of the Fungi, Mycetozoa, 

 and Bacteria. Oxford. 



Conn. Agricultural Bacteriology, 2d ed. Philadelphia, 1909. 



