628 LABORATORY HINTS 



MALARIAL PIGMEXT : WHERE IT IS AND HOW TO 



LOOK FOR IT. 



This pigment is found in the parasites, rarely in the polymorpho- 

 nuclears and in large mononuclears. When in the latter it is 

 ])athognomonic of malaria. The pigment is carried by the cells to the 

 liver and spleen. The endothelial cells of the capillary also take it 

 up and may then become detached. If pigment is found elsewhere it 

 is not malaria. The pigment is nearly always intracellular. 



The mononuclears soon give it up again, so that to find these cells 

 carrying it indicates that malaria was progressing at Jhe time. 



In the liver it is found in the small cells of the connective tissue 

 type with a dark staining nucleus which penetrates between and into 

 the liver lobules. The containing cell becomes degenerate, the nucleus 

 stains faintly, and the pigment appears in larger clumps. 



Later, the pigment alone remains, lying in the connective 

 tissue. 



This latter stage is reached from the twentieth to the thirty-second 

 day, so that from the examination of the liver one can tell how long 

 the malarial process has been going on, and it indicates that the liver 

 was active at the time of death. 



In the spleen pigment is always present, chieflv in the macro- 

 phages, which may give a dark appearance to the organ on section 

 according to the number of malarial attacks and the amount of pigment 

 deposited. 



A slaty-black colour is almost diagnostic. 



Malarial pigment consists of : — 

 (i) Melanin, which is diagnostic. 



(2) H^emosiderin, not diagnostic. 



(3) Iron-bearing granules, not diagnostic. 



Melanin contains iron, but in such firm combination that it does 

 not give the iron reaction. It is insoluble in acids, soluble in alkalies, 

 insoluble in alcohol. 



H^emosiderin is insoluble in acids and alkalies, but soluble in 

 alcohol. 



It does not require staining to be seen. It is said not to contain 

 iron. Carbol thionin stains it violet. 



The iron-free granules contain iron in inorganic combination, so 

 will give the reaction for free iron. The more acute the hsemolytic 

 process, the more numerous the iron granules ; the more chronic the 

 process, the more numerous are the yellow granules. 



In blackwater fever there is much blue pigment; and in anky- 

 lostomiasis much yellow pigment. The haemosiderin and the iron- 

 free granules are seen in any disease causing haemolysis, as pernicious 



