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ESSENTIALS OF CHEMICAL PHYSIOLOGY 



blood to froth, and the bulb, h, is called the froth-chamber, as it intercepts 

 the froth, preventing it from passing into the rest of the apparatus. 



The pump is used in the following way: I is filled with mercury, the 

 level in I and o being the same ; Ti is closed ; o is then lowered, and when it 

 is 30 inches lower than the stopcock, Zr, the mercury in I falls also, leaving 



Fig. 79.— Diagram of PflUger's pump. 



that bulb empty ; j being closed and / open, Ic is then opened, and the air in 

 a, b, d, &c. rushes into the Torricellian vacuum in Z ; / is closed and j opened ; 

 the reservoir, o, is raised ; the mercury in 7 rises also, pushing the air before 

 it, and it bubbles out into the atmosphere through the mercury (the tube, h, 

 is not at this stage in position). When I is full of mercury, k and j are once 

 more closed and o is again lowered ; when I is thus rendered once more a 



