150 SPECIAL PHYSIOLOGY 



5. What are the dimensions of the red cells? 



6. Are there any variations in the size of the red cells? 



7. What are the maximum and minimum dimensions? 



8. What percentage are large, normal, or small? 



9. How may the elasticity of the red cells be demonstrated? 



10. What are the causes of the movements of the red cells? 



11. How are the red cells arranged? 



12. What causes crenation? 



13. What causes vacuolation? 



14. How large are blood platelets? 



15. What happens to the red cells in the presence of water? 



16. What happens to the red cells while drying in the air? 



17. What happens to the red cells when spread by pressure? 



18. Of what does a red cell consist? 

 White Cell. 1. Describe a white cell. 



2. How can the shape of a white cell be demonstrated? 



3. How can you demonstrate the elasticity of a white cell? 



4. How can you demonstrate the nucleus of a white cell? 



5. What are the dimensions of a white cell? 



6. Are there any variations in the size of a white cell? 



7. What are the percentages of the various sizes? 



8. Do they float readily under the cover-glass? 



9. What becomes of the white cell in the presence of water? 



10. What becomes of the white cell while drying in the air? 



11. Of what does a white cell consist? 



C. Spreading Blood for Staining. 



Glass Slide Method. Take one of the carefully prepared glass 

 slides and allow the drop of blood to touch it near one end, as 

 shown in Fig. 71. Place this on a table and hold the glass by 

 placing a finger on the slide beyond the drop of blood, as shown in 

 figure. Then take a ground-glass slide, hold by the edge between 

 the thumb and fingers of the other hand, and place the edge of one 

 end between the drop and the finger holding the slide, as shown in 

 figure. Now, with a free-arm movement from the shoulder, quickly 

 sweep the second slide across the remainder of the surface of the 

 first slide, exerting a very slight but even pressure; the resulting 

 smear will be as shown in lower slide of figure. 



The speed can be made, slowly by exerting more pressure, but it 

 will not give a thin, even film of blood, and it will distort the cor- 

 puscles more. Make a number of smears for further use. 



Cover-glass Method. Take a cover-glass between the thumb 

 and first finger of each hand, with the heated surface up in the left 

 and the heated surface down in the right hand, as shown in Fig. 72. 

 Allow the center of the glass in the left hand to just touch the fresh 



