8 ELEMENTARY BIOLOGY. [l. 



crushed transparent sacs ; the soft crushed stained 

 protoplasm. 



5. Repeat observation 3, running in iodine solution instead 

 of magenta. The protoplasm stains brown ; the rest of 

 the cell remains unstained. Note the absence of any 

 blue coloration; starch is therefore not loresent. 



G. Treat another specimen with potash solution, running 

 it in as before : this reagent dissolves out the proto- 

 plasm, leaving the sac unaltered. 



7. [Sow a i&w yeast-cells in Past3ur's solution in a moist 

 chamber and keep tliem under observation from day to day ; 

 watch their growth and multiplication.] 



8. [Endogenous division: take some yeast which has been 

 grown in Pasteur's solution at a temperature below 20° C. ; 

 spread it out in a thin layer on fresh cut potato slices or on 

 some plaster of Paris, and place with wet blotting papei' 

 under a bell-jar : examine from day to day with a very 

 high power (800 diam.) for ascospores, which will probably 

 be found on the fifth or sixth day.] 



B. Physiology. 



(Conditions and results of the vital activity of Torula.) 

 1. Sow a fair-sized drop of yeast in — 

 a. Distilled water. 

 h. 10 per cent, solution of sugar in water. 



c. Pasteur's fluid without the su"ar 



d. Pasteur's fluid with sugar. 

 [e. Mayer's pepsin solution'.] 



1 Mayer's solution (with pepsin) = 



15 per cent, solution of sugar-candy ■20 co. 



Dihydropotassic phosphate o"i grin. " 



1/ Calcic phosphate o'i"rm. 



""^ Magnesio sulphate o-igrm! 



repsm o'23grm. 



