LIST OF ILLUSTRATIONS 



ALL the photomicrographs which illustrate this book were takea 

 with the apparatus described in Chapter II. The objective used for 

 those taken with the higher magnification was a 2-mm. apochromatic 

 lens (Zeiss) N. A. 1 '30. The objectives employed for taking photo- 

 graphs of a lower magnification were Zeiss D and Zeiss A. The eye- 

 piece used in all of them was a "high-power projection eye-piece'^ 

 (Watson). 



In the actual preparations, as observed through the microscope, a 

 stereoscopic view of the dividing cells can be obtained, which facilitates, 

 the demonstration of the different phases. Unfortunately, this stereo- 

 scopic effect cannot be seen in the prints, although an examination of 

 them with a hand magnifying-glass will remedy the deficiency to some 

 extent. 



The photograghs have all been produced without any alteration of 

 the original negatives. 



FIG. PAGE, 



1. A typical field seen by the in-vitro method of staining. The leuco- 



cytes are staining gradually Frontispiece. 



2. The photomicrographic apparatus. The microscope is ready to 



be used for direct observation. The gas-burner can just be seen 

 at the lower end of the wooden plank. (N. B. The sheets of 

 white paper have been placed in this position in this and the next 

 photograph in order to " show up " the apparatus.) 23- 



3. The apparatus ready for photography. The mirror is swung aside, 



and the eye-piece attached to the camera is inserted into the 

 microscope 25- 



4. The photomicrographic apparatus. Showing positions of water- 



cooling tank and Nernst burner. The microscope mirror is in 

 position for direct observation 29- 



5. The photomicrographic apparatus. The microscope mirror is ' 



swung aside for photography 31 



6. The granules of the leucocyte are gradually becoming stained. 



The red cells are unstained. Low power 45- 



7. The leucocyte's granules are stained. Its nucleus is unstained. 



The pseudopodia are extruded in response to atropine, which is 

 diffusing into the cell as well as the stain 45- 



XXV 



