ORGANIZED FERMENTA. 63 



action is stopped, by a large accumulation of its own 

 products. 



The organized ferments contain albumin, fat, cellu- 

 lose, and some inorganic salts. They survive a high tem- 

 perature better than the enzymes, but are killed at 100 

 except certain spore forms. Moisture is necessary for them 

 to act. 



As is the case with the enzymes, a sufficient amount 

 of their products stops their further action. This is the 

 effect of alcohol upon the yeast-plant. 



150. Add a little yeast to a dilute solution of cane- 

 sugar in water and keep it for some time at the body-tem- 

 perature. 



Test the solution with Trommels test. The copper 

 compound is reduced by the glucose and Ia3vulose which 

 have been formed from the sucrose by the invertin of the 

 yeast. If allowed to stand a long time the glucose is 

 changed by the yeast to alcohol and carbon dioxid. 



151. Stir a little compressed yeast into lukewarm 

 water in a test-tube, and after it has stood a few minutes, 

 add a few drops of chloroform and mix thoroughly by 

 shaking. Fill the rest of the tube now with dilute cane- 

 sugar solution and let it stand inverted for twenty-four 

 hours in a warm place, as in Experiment 31. The alco- 

 holic enzyme (zymase) does not act in presence of chloro- 

 form, so that there is no alcoholic fermentation with a 

 formation of carbon dioxid. 



152. Test the liquid with Trommer's test. It re- 

 sponds to the test, showing that the inverting enzyme is 

 iwt destroyed, but has decomposed the cane-sugar, as be- 

 fore, to glucose and lavulose. 



