MOLDS, YEASTS, TORULAE, AND BACTERIA 189 



6. After the gelatin has solidified, paint the top of 

 the glass ring of a Bottcher Moist Chamber with 

 vaselin and invert the cover slip, gelatin down. Do 

 not neglect to place a small amount of water inside the 

 moist chamber. 



7. Examine under the microscope and make a 

 sketch corresponding to the figures on the cover slip 

 and make a mark for all single cells observed. It is 

 possible then to find the cells again by comparing the 

 cover slip with the sketch. 



8. Incubate at room temperature. 



9. Observe from day to day the growth of colonies 

 from single cells. 



10. When the colonies are large enough to be picked 

 up with a platinum needle, inoculate several tubes of 

 liquid wort with the colonies. 



11. Incubate at 25° C. and after growth has 

 appeared transfer the sediment from each tube to a 

 flask containing Hquid wort. 



12. Incubate these flasks and study the cultures by 

 making microscopic examination and stains, study the 

 film and the sediment separately, inoculate fermenta- 

 tion tubes with the various carbohydrates, and inoculate 

 gypsum blocks. Also note the aroma, and determine 

 the amount of alcohol formed. 



EXERCISE 6. A STUDY OF LABORATORY CULTURES 



Prepare cultures from Saccharomyces cerevisiae, 

 Sacch. pastorianus, and Sacch. ellipsoideus on liquid 

 wort. After 24 hours' incubation transfer to all media 

 and study these yeasts in the same manner as described 

 as to gas formation, film and sediment formation, spore 

 formation, etc. 



