XII.] STRUCTURE OF BLOOD-VESSELS. 133 



e. The elasticity of the red corpuscles, observing 

 the way in which they bend and become 

 deformed, and then regain their normal shape. 



6. Remove the cover-slip, and soak up the fluid on 

 the web ; touch the middle of the web with 

 the tip of a pointed glass rod that has been 

 dipped in creosote 1 , so as to leave a minute 

 drop on the web, and replace the cover-slip. 

 The early stages of inflammation may be 

 seen. Observe in succession 



a. The dilatation of the arteries, the much more 

 distinct appearance of the capillaries, and the 

 enlargement of the veins, accompanied by a 

 quickening of the current. 



b. A slowing of the current, the vessels remain- 

 ing dilated. 



c. The white corpuscles increase in number in 

 the peripheral zone of both arteries and veins, 

 in the latter the white corpuscles begin to 

 cling to the sides, at first for a time only, 

 then being carried off, later permanently 

 until the veins have a more or less complete 

 lining of white corpuscles. In the capillaries 

 the white corpuscles and also, though less 

 frequently, the red corpuscles, stick to the 

 capillary walls, partially or completely block- 

 ing the way. Later the way becomes com- 



1 Instead of this, olive oil containing 1 to 2 p. c. of croton-oil may 

 be used. In either case the irritant should be washed off if stagnation 

 sets in rapidly. 



