16 



THE ESSENTIALS OF HISTOLOGY 



LESSON V. 



THE AMCEBOID PHENOMENA OF THE COLOURLESS 

 BLOOD-CORP USCLES. 



1. MAKE a preparation of blood from, the finger in the usual way. Draw 

 a brush just moistened with oil around the edge of the cover-glass to check 

 evaporation. Place the preparation upon a ' warm stage,' and heat this to 

 about the temperature of the ody (38 C). Bring a white corpuscle under 

 observation with the high power, and watch the changes of shape which it 

 undergoes. To become convinced of these alterations in form, make a series 

 of outline sketches of the same corpuscle at intervals of a minute. 



The simplest form of ' warm stage ' is a thin copper plate of about the size 

 of an ordinary slide, perforated in the centre and with a long tongue of the same 

 metal projecting from the middle of one edge (fig. 15). The copper plate is 

 firmly cemented with sealing-wax to a glass slide which rests upon the stage 



FIG. 15. SIMPLE WARMING APPARATUS, COMPLETE, SHOWN IN OPERATION. 



of the microscope. The preparation, which should be made upon a rather 

 thin slip of glass, is put on to the warm stage and pressed into contact with 

 it by the brass clips. Heat is applied to the copper tongue by a small spirit- 

 lamp flame, and a greater or less amount is conducted to the warm stage 

 and the superjacent preparation according to the point to which the flame is 



