1126 PATHOGENIC PROTOZOA 



reviewed by Roubaud,* who has been much impressed by the prac- 

 tical disappearance of malaria from France without a corresponding 

 diminution of anophelines capable of acting as carriers. In La 

 Vendee, a Department of France, are regions where there are many 

 swamps and few cattle or domestic animals and it is in such regions 

 that human malaria remains; in other regions, abundantly supplied 

 with domestic animals the disease has practically disappeared al- 

 though anophelines still may be found in the animal shelters. He 

 believes that the insects prefer the blood of cattle and horses to that 

 of human beings, and that a sufficient number of animals will protect 

 the human inhabitants against infection in an otherwise malarious 

 locality. The method is of sufficient importance to merit further 

 study and trial. 



In conclusion, it may be affirmed that any district, no matter 

 how notorious, may be freed from malaria, if necessity demand it 

 and money be forthcoming, by means of the above measures. 



Pathology. The pathological features of the disease are quite 

 definite ; at autopsy there is evidence of some secondary anemia, due 

 to the destruction of enormous numbers of erythrocytes ; the hemo- 

 zoin, in well-marked cases, accumulates in the viscera until they 

 are chocolate or slate colored; the spleen is enlarged and friable, 

 and the liver and kidneys may show cloudy swelling. In smears 

 prepared from the spleen, liver, kidneys, brain and bone marrow, 

 parasites and hemozoin will be found, although the former may not 

 be numerous. The distribution of the parasites is usually unequal, 

 but they are often present in the spleen and brain in greatest 

 numbers. 



The origin of the pigment has already been described; it is 

 phagocyted and accumulates in the viscera, but after a time dis- 

 appears in some unknown way ; its presence, therefore, is an indica- 

 tion of malaria in recent years. It must be distinguished from 

 hemosiderin, a yellowish pigment found in the viscera after extensive 

 destruction of red blood cells. Hemozoin is soluble in alkalis and 

 insoluble in acids, water, chloroform, alcohol and ether, while hemo- 

 siderin is insoluble in acids and alkalis but soluble in alcohol. Both 

 contain iron, yet the former (hemozoin) does not give a Berlin blue 

 reaction, while it is present with the latter. 



* Roubaud, E., Les Conditions <le nutrition des anopheles en France et le role 

 du Betail dans la prophylaxie du paludisme. Ann. Inst. Pasteur., Paris, 1920, 

 34, 181. 



