xii CONTENTS 



IV. The methods of sowing and cultivating aerobic 



organisms. 



Introduction, - 67 



Section I. Instruments used for sowing cultures, - 67 



Section II. The methods of solving cultures, 70 



Section III. Conditions essential to satisfactory growth, 72 



Section IV. The examination of cultures, 73 



Section V. The methods of storing cultures, - 75 



V. The isolation of aerobic micro-organisms in pure 



culture. 



Introduction, - - 76 



Section I. Mechanical methods, - 76 



(1) Isolation by dilution, p. 76. (2) Isolation by dissemination, 

 p. 77. 



Section II. Biological methods, 83 



(1) Heat, p. 84. (2) Cultivation at the optimum temperature, 

 p. 84. (3) Cultivation on special media, p. 85. (4) Animal inocu- 

 lation, p. 85. 



VI. The cultivation and isolation of anaerobic micro- 



organisms. 



Introduction, - 87 



Section I. The methods of abstracting air from culture 



media, - 87 



(1) By boiling, p. 87. (2) By displacing the air with an inert 

 gas, p. 88. (3) By absorbing the oxygen, p. 89. (4) By the use of 

 a vacuum, p. 90. (5) Tests for oxygen, p. 92. 



Section II. The cultivation of anaerobic organisms, - 92 



(1) In liquid media, p. 92. (2) In solid media, p. 99. 



Section III. The isolation of anaerobic organisms, - 101 



(1) Plate method, p. 101. (2) Tube method, p. 103. 



Section IV. Vacuum incubators, - 104 



VII. The Microscope. 



Introduction, - 106 



Section I. The microscope stand, - 106 



Section II. The optical parts of the microscope, - - 107 



A. The objectives, p. 107. (1) Magnification, p. 107. (2) Spherical 

 aberration, p. 110. (3) Angular aperture, p. 112. (4) Numerical 

 aperture, p. 112. (5) Resolving power, p. 112. (6) Brightness of 

 image, p. 113. (7) Definition, p. 114. (8) Chromatic aberration, 

 p. 114. (9) Flatness of image, p. 115. B. The eyepieces, p. 116. 



Section III. The care of the microscope, - - 117 



Section IV. The method of using the microscope, - 118 



