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 /T?-' V CHAPTER. } 



C f ^4^r/^^. 



^ Capillary Circulation. 



Pith a frog without haemorrhage. Pin web of foot over a hole in 

 a board. Keep rr^j06t with saline. Cover with coverglass if neces- 

 i sary. Focus on web with CPp. microscope. 



1. Blood Vessels. Notice the movement of the blood within 

 the blood vessels of varying size and irregular course. 



2. Velocity of flow. Is the motion equally rapid in all the 

 vessels? If not are the slower currents in the larger or smaller 

 channels? How can you distinguish an artery from a vein? Com- 

 pare thickness of walls and character of flow. Is the velocity 

 equally rapid in all parts of a vessel at a given point? Why is this 



'so? Of what physiological importance? 



3. Pulse. Have you seen evidence of intermittent force acting 

 upon the corpuscles? If so describe its influence. Determine 

 whether this intermittent force makes itself evident in all of the 

 vessels. If not, in which class of vessels is it present? Can you 

 detect pulsations in a small artery? Vein? Capillary? 



4. Size of Vessels. Do you observe any variation in the size 

 of a given vessel? Carefully measure with the eyepiece micro- 

 meter and determine. 



5. Do you see small vessels appear, apparently new, from time 

 to time? How do you account for this? Do you see small vessels 

 apparently disappear? 



6. Corpuscles. In the frog the red corpuscles are larger than 

 the white. With high power study the behaviour of the red cor- 

 puscles. Do they change shape? If so, under what conditions? 

 Do you see evidences of flexibility and elasticity? Are the red 

 corpuscles nucleated? Study the white corpuscles. Where are 

 they the most numerous in the blood stream? How do you account 

 for this distribution? 



7. Capillary Flow. Estimate the velocity, of a single corpuscle 

 by means of the micrometer eyepiece and stop watch. Of what 

 physiological significance is this slow rate? 



273 





