HOW REDWATER GOT ITS NAME 181 



were by no means rare, but there was no way of 

 telling whether the numbers were due to multiplica- 

 tion of the organism within the corpuscle, or were 

 the result of multiple infection. 



The various Piroplasmata (genus Babesia) are 

 essentially parasites dwelling within the red cor- 

 puscles of their hosts. What effects have they upon 

 the animals harbouring them ? The red corpuscles 

 of the blood contain haemoglobin, a substance cap- 

 able of absorbing oxygen and of transporting it to 

 the tissues of the body. When Babesia occur 

 in the blood, the numbers of red blood-corpuscles 

 may become only about two-thirds the ordinary 

 number, the others having burst. The number of 

 blood - elements being thus reduced, the blood 

 becomes very anaemic and watery, and the animals 

 are much weakened. The blood-pigment, haemo- 

 globin, is set free by the bursting of the corpuscles, 

 and is often excreted by the kidneys, thus giving the 

 name " redwater " to the disease. Besides altera- 

 tions in the corpuscles, bile-pigment occurs in the 

 blood-serum, accounting for the marked jaundice 

 seen, for instance, in dogs. Enlargement of the 

 spleen is common both in cows, horses, and dogs, 

 at any rate in the tropics. A loss of weight always 

 occurs and leads to great emaciation in chronic cases. 

 Death is the usual result, though some animals 

 acquire a partial immunity, when they habitually 

 harbour a few parasites in their blood without being 

 adversely affected thereby. They then are even 

 more dangerous than obviously sick animals, since 

 they act as reservoirs of the disease. 



