THE STUDY OF YEASTS 121 



ogists (p. 134). In describing the wort culture use the 

 descriptive chart terms under the heading " Nutrient 

 broth." 



8. If any gas has formed in the fermentation tubes 

 mark the level of the liquid in the long arm with a 

 wax pencil and record the percentage of gas, using the 

 gasometer. 



9. Test quantitatively and qualitatively for gas in the 

 fermentation tubes. (See Exercise 41, p. 117). 



10. What is the ratio of the CO2 to H2 and other gases? 

 Is this ratio constant for all fermentations? For one 

 organism? Why? Do all organisms cause fermentation? 

 Why? What causes fermentation? 



11. Examine adhesion cultures after forty-eight hours 

 and seventy-two hours and make drawing of colony forma- 

 tion. 



12. Study the fourteen to twenty-day old wort cultures 

 in hanging drop for endospores. When do these form? 

 Why? 



REFERENCES 



HANSEN, E.: Practical Studies in Fermentation, pp. 215-217. 



LAFAR: Technical Mycology, Vol. II, Part II, pp. 394-406, 430- 



436. 



EYRE: Bacteriological Technic. Second Ed., p. 7. 



