THE DIGESTIVE TEACT. 



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emigrated colorless blood-corpuscles (so-called " leucocytes"). The deter- 

 mination as to the particular source of these corpuscles, in the present condi- 

 tion of our knowledge, is impossible. The diphtheritic exudation is of exactly 

 the same character as the croupous ; its nature is determined by its deep site 

 in the tissue of the mucosa, and is often recognizable under the microscope by 

 the presence of isolated globular clusters of lymphatic (adenoid) tissue, from 

 which putrefaction starts. The globular nests filled with micrococci originate 

 from such clusters of lymphatic tissue. 



