THE BLOOD PLATELETS 



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fixing fluids, which have been recommended for the display of blood platelets, 

 may owe their virtues, not to the fact that they preserve, . but to the fact 

 that they produce platelets. These may therefore be regarded as pre- 

 cipitates produced in the plasma directly it undergoes alterations, their 

 appearance being the first sign of changes in this fluid. They consist of 

 some substance probably belonging to the class of nucleo-proteins, and 

 like these yield a precipitate on gastric digestion, and have a specific affinity 

 for basic dyes. Even after their first appearance they are unstable, tending 

 to undergo further alteration and to give off to the surrounding plasma 

 substances which play an important part in the formation of fibrin ferment 

 and in the coagulation of the blood. 



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