226 DISEASES DUE TO PROTOZOA 



cessive cells by a curious extracellular and intracellular 

 crescent-shaped body. 



The anatomy of these plasmodia is of great intricacy, 

 and undergoes so many changes that it is hardly 

 desirable to go into detail here. Suffice it to say that 

 it is a body when adult somewhat larger than a red 

 blood cell, full of actively moving granules. The 

 young forms are homogeneous, and are found with 

 the greatest difficulty except when specially stained. 

 They probably get all their granules from the destruc- 

 tion of the red blood cells. Some adult forms have 

 flagella about their wall. The power of producing 

 disease lies partly in their destruction of the important 

 cells of the blood and partly in a poison they produce. 

 The internal organs, especially the spleen, are injured 

 first by the damage to the blood, and secondarily by 

 the extra work thrown on them in trying to destroy 

 the parasites and to remove the pigment which is 

 liberated by the cellular disintegration. A slight 

 immunity remains after an attack. There is a relative 

 racial immunity among the negroes. The cases that 

 do not wholly recover or that have remote recurrences 

 are said to be harboring quiescent parasites in the 

 spleen. A chronic inflammation of this organ often 

 results. 



Diagnosis. The disease is diagnosticated by making 

 fresh or dried and stained preparations of the blood and 

 examining them under the microscope. Should malaria 

 organisms be present, faint, irregular shadows or larger 

 bodies filled with dancing granules are seen in the 

 unstained blood, while in stained smears fairly well- 

 colored parasites containing quiet granules will be 



