YEAST. 37 



III. Reproduction. 



1. Soiv a few cells of freshly moistened compressed 



yeast in a few drops of Pasteur's fluid on a 



slide. Cover, and examine with a high power. 



Compare the structure of the cells with that 



of growing yeast. 

 Sketch. 



Put the slide on a zinc rack, stand the rack in a 

 dish containing half an inch of water, and cover 

 with a bell-jar (inoist chamber). 

 Examine from day to day to see multiplication 

 by budding. (Gemmation.) 



2. Examine with a high power yeast-cells in which 



ascospores have been formed. (Endogenous 

 Division.) 

 Sketch. 



IV. Chemical Experiments. 



1. Mount in water on a slide a very small 



amount of powdered starch. Look at it with 

 a low power. Draw iodine solution under 

 the cover-glass. Look again ; note the 

 effect of iodine solution upon starch. 



2. In the same way treat yeast upon the slide 



with iodine. What inference is to be 

 drawn as to the presence of starch loithin 

 the yeast-cell ? 



3. Treat another specimen of yeast with magenta 



solution. What parts of the yeast plant are 

 stained ? 



