DISEASES OF THE BLOOD. 91 



accounted for tlie frequency of symptomatic fever consti- 

 tuting general disorder as a result of local inflammation. 

 While the tendency to this and other fevers is not very 

 marked in the ox^ the liability to specific blood poisons is 

 considerable, and we shall have to treat of many special 

 disorders which devastate our herds and have proved the 

 scourge of the agriculturist from time immemorial. The 

 relatively small amount of blood of the ox and the larger 

 size of the red globules may be, perhaps, considered the 

 cause of the immunity from general fever and from inflam- 

 mation leading to ill effects after major operations, which is 

 observable in bovine practice as compared with equine. 

 At the same time we must remember, too, that some parts 

 of the body, as the alimentary canal, receive a great deal 

 of blood, and that the venous system is remarkable for its 

 largeness as compared with the arterial. 



A. Nutritive Excess. — Hypeeteophy op the Blood (Wat- 

 son), Plethoea — vulgarly known as Fulness of Blood — 

 results from high activity of the blood-forming organs, 

 whereby the blood becomes loaded with red and white 

 corpuscles. This condition is denoted by redness of 

 visible mucous membranes with a tendency to active 

 haemorrhages, a full, bounding pulse, high constitu- 

 tional vigour, and tendency to thrive and lay on fat. 

 Such a state of the body as this can not be considered 

 disease, but predisposition to apoplectic and acute inflam- 

 matory affections. We are familiar with the frequency 

 of black quarter in yearling calves in a highly plethoric 

 condition. The causes of plethora are excess of food, 

 vigour to appropriate nutritive matters, and insufficient 

 exercise to bring about a demand for fresh material pro- 

 portioned to the supply. Treatment must therefore con- 

 sist in urgent cases in abstraction of blood, whereby 

 plethora is at once relieved ; in gradual reduction of 

 diet, exhibition of laxatives, and giving the animal a wide 

 and not too rich pasture to graze over. It is the custom 

 to insert a seton in the dewlap that the resulting suppura- 

 tion may drain away the precursors of the red corpuscles. 

 This certainly lessens the predispositions above mentioned. 



