Paludism in Horses. 583 



Course. Duration. In very acute cases death may take place 

 in a few hours. More commonly illness lasts from three to six days. 

 In certain instances it becomes chronic and may last two or even 

 three months, the early congestion of the mucosae giving place to 

 pallor and anaemia with advancing emaciation, dropsies and finally 

 maiasmus and death. 



Lesions. These are mainly in the blood, red globules being 

 distorted, crenated, massed in clusters and greatly diminished in 

 numbers so that the liquid appears thin and watery. The muco- 

 sae, internal organs and serosae are petechiated and the serous 

 cavities contain a yellowish serum. A yellowish tint pervades 

 the white tissues generally. The liver is congested, virtually 

 gorged with blood, enlarged and yellow or yellowish brown. The 

 spleen is greatly enlarged, blood gorged, and shows irregular, 

 rounded swellings indicating the seats of extravasation of blood. 

 In some instances rupture has taken place. The kidneys are con- 

 gested, enlarged, softened and of a brownish red or black color, 

 with circumscribed extravasations especially in the cortical area. 

 The lungs are violently congested, with many areas of blood 

 extravasation, and they do not collapse when the chest is opened. 

 The heart is petechiated, with a parboiled aspect and shows areas 

 of commencing necrosis or fatty degeneration. 



In the chronic form the watery condition of the blood is remark- 

 able, the serous cavities (peritoneum, pleurae, pericardium, arach- 

 noid) contain considerable effusion, dropsical conditions of the 

 limbs and dependent parts of the body are common, the lungs 

 show hepatization and minute centres of suppuration, and other 

 viscera may show fibroid degeneration. 



Prevention. It is advisable to keep susceptible horses from the 

 low marshy infected lands from June to November and to avoid 

 especially water that is drawn from such lauds. It is not needful 

 to take the stock to any very marked elevation provided the land 

 is dry and free from wet or swampy areas. The native horses or 

 those that have been long in the marshy district and have thus 

 secured a partial immunity may profitably replace the more 

 recently imported and susceptible horses during the dangerous 

 summer months. 



The habit of the paludal protozoa of securing their transfer 

 from one of the higher animals to another through the intermedia- 



