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TRANSPORT. 



16. Vertebrate blood. 



(a) Blood treated with a soluble sulphate to remove the calcium and then centrifuged 



to show the relative volumes of corpuscles and plasma. 



(b) Clotted blood : note the clot and the serum. 



(c) Plasmolysis. 



17. Heart beat of a toad. Examine the beating of the heart of an anaesthetized 

 toad, noting the order in which the chambers contract. 



18. Circulation of the blood in the bladder of a toad. Watch the rapid 

 rhythmic flow in the arteries, the slow flow in the capillaries and the rapid even flow in 

 the veins. 



