Messrs. Barnard and Hewlett. Method of [Mar. 28, 



IV. Amount = 3 c.c. of yeast cream. Speed 700 — 750 revolutions per minute, 

 (a) After 10 minutes' grind. 

 Percentage of crushed cells = 



(b) After 20 minutes' grind 

 Percentage of crushed cells = 85 



(c) After 30 minutes' grind. 

 Percentage of crushed cells = 84 



Crushed cells = 216, uncrushed cells = 54. 

 Crushed cells = 192, uncrushed cells = 32. 

 Crushed cells = 210, uncrushed cells = 40. 



Speed 700 — 750 revolutions per minute. 

 Crushed cells = 46, uncrushed cells = 



Crushed cells = 127, uncrushed cells = £ 



V. Amount = 18 c.c. of yeast cream, 

 (a) After 10 minutes' grind. 

 Percentage of crushed cells = 



(6) After 20 minutes' grind. 

 Percentage of crushed cells = 56. 



(c) After 30 minutes' grind. Crushed cells = 154, uncrushed cells = 65. 

 Percentage of crushed cells = 77. 

 VI. Amount = 6 c.c. of jeast cream. Speed 500 revolutions per minute. 



After 20 minutes' grind. Crushed cells = 219, uncrushed cells = 53. Percentage 

 of crushed cells = 80'5. 

 VII. Amount = 12 c.c. of yeast cream. Speed about 500 revolutions per minute. 



After 20 minutes' grind. Crushed cells = 178, uncrushed cells = 79. Percentage 

 of crushed cells = 69. 

 VIII. Amount = 12 c.c. of yeast cream. Speed 2000 revolutions per minute. 



After 20 minutes' grind. Crushed cells = 141, uncrushed cells = 59. Percentage 

 of crushed cells = 70'5. 

 IX. Amount = 12 c.c. of yeast cream. Speed 360 revolutions per minute. 

 After 20 minutes' grind. Crushed cells = 125, uncrushed cells = 

 of crushed cells = 39 - 5. 

 The machine did not run well at this low speed. 

 X. Amount = 12 c.c. of yeast cream. Speed 1400 revolutions per minute. 

 After 20 minutes' grind. Crushed cells = 134, uncrushed cells = 

 of crushed cells = 64. 

 XI. Amount = 6 c.c. of yeast cream. Speed 828 revolutions per minute. 



After 20 minutes' grind. Crushed cells = 85, uncrushed cells =18. Percentage 

 of crushed cells = 82 - 5. 

 XII. Amount = 18 c.c. of yeast cream. Speed 750 — 800 revolutions per minute. 



After 20 minutes' grind. Crushed cells = 233, uncrushed cells = 100. Percentage 

 of crushed cells = 70. 

 XIII. Amount = 6 c.c. of yeast cream. Speed 700 — 750 revolutions per minute. 



After 20 minutes' grind. Crushed cells = 188, uncrushed cells = 68. Percentage 

 of crushed cells 735. 



In Plate 1, a is a photo-micrograph of unground yeast, b and c the same 

 after grinding for 15 and 30 minutes respectively. 



