CHAPTER II. 

 PRODUCTS OF THE GROWTH OF BACTERIA. 



The splitting up of animal and vegetable matter by the bac- 

 teria results in the formation of various products, which may 

 possess certain characteristics. Thus some of the products 

 of bacterial growth are phosphorescent, some are marked by 

 more or less vivid color, others again by poisonous properties. 



Phosphorescence. — Bacteria whose cultures exhibit phos- 

 phorescence have been found in the ocean and in fish. 



Chromogenic Bacteria. — Many bacterial growths display 

 brilliant coloring. The different species of sarcinse are re- 

 markable for forming highly-colored growths; some of them 

 are rose-red, some orange-yellow, some lemon-yellow, and so on. 

 The bacillus prodigiosus presents a brilliant red growth whose 

 rapid development is said to have formed the basis for the so- 

 called "Miracle of the Bleeding Host" (see page 5). The 

 bacillus pyocyaneus in culture gives a brilliant green fluores- 

 cence and is responsible for the color of blue or green pus. 

 Bacilli which exhibit a green fluorescence in cultures are com- 

 mon in water. In cultures on potato or agar the colors of 

 the chromogenic forms are usually well shown. The pig- 

 ment formed by the chromogenic bacteria is not produced in 

 the cells themselves. These are colorless. The color is due 

 to substances excreted by the cells or formed from material in 

 the culture-media. 



Ferments or Enzymes.*— Many bacteria form ferments 

 which have the power of dissolving proteid substances in a 

 manner similar to trypsin. The liquefaction of gelatin is a 



♦Consult Buxton. Mycotic Anzymes. American Medicine. July 25, 1903. 



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