94 LABORATORY EXERCISES. 



2. How many elevations can you distinguish 

 on the dorsal surface of the mid-brain? 

 '(These are the optic lobes which connect 

 with the eyes.) 

 E. Cranial nerves (Dem.). 



From what region of the brain do each of the 

 following pairs of nerves originate and what is 

 their distribution? 



1. First pair or olfactory. 



2. Second pair or optic. (Note crossing of 



these nerves on ventral surface of brain.) 



3. Third, fourth, and sixth pairs. 



4. Fifth and seventh pairs. 

 4. Eighth pair or auditory. 



6. Ninth, tenth, eleventh, and twelfth pairs. 



48. STUDY OF YEAST. 



Materials for home work: Compressed yeast, molasses; two pint 

 bottles, small bottle, tin cup; refrigerator; stove; thermometer. 



Materials for class demonstrations: (A, 9, 10, D); Flask, rubber 

 cork (two holes); U-tube, test-tube; chemical thermometer; glass 

 and rubber tubing; water-bath; condenser; compound microscope 

 (500 diameters), slide; cover-glass; lime-water, eosin or methyl 

 violet. 



A. Study of the growth of yeast. 



Mix about an eighth of a cake of compressed 

 yeast in a tablespoonful of water and stir until 

 a smooth thin mixture is formed. Add this to 

 about a half -pint of water in which a table- 

 spoonful of molasses has been dissolved. Place 

 this mixture in a wide -mouthed bottle which 

 holds about a pint; stopper very loosely. 



