CHANGES IN THE BLOOD. 87 



in some cases its quantity is notably increased, particularly if 

 inflammation of any organ is present. (4.) The solids of the serum 

 are not found much altered. (5.) The quantity of water is more 

 or less increased in proportion to the diminution of the globules. 



LEUKEMIA OR LEUCOCYTHEMIA 



Is a condition of the blood characterised by a large increase in 

 the nimiber of the white corpuscles, associated with a new 

 formation of lymphatic tissue (lymphadenoma) in the lymphatic 

 glands, spleen, and other organs; but the association of leukaemia 

 with lymphadenoma is not constant. 



An increase of white corpuscles is also witnessed in some 

 cases of farcy and glanders ; but the true nature of leuktemia 

 seems to depend more upon an inability in the white and lymph 

 corpuscles to form red blood globules, than upon any actual 

 growth of lymphatic tissue. 



POLYiEMIA, PLETHORA. 



The possibility of there being at any time an increased 

 quantity of blood in the animal body — plethora — is denied by 

 some observers. The condition, however, is recognised by 

 veterinarians as one of not infrequent occurrence, more especially 

 in young fast-thriving animals, when fed upon very highly 

 nutritious food. The occurrence of a general plethoric con- 

 dition is also recognised by Sir Thomas Watson, who says — 

 " Perhaps it may not be so obvious that the whole quantity of 



blood throughout the body is sometimes in excess 



Full living and a sedentary life are causes likely to occasion 

 general plethora, and they do occasion it. The full diet, so long 

 as the digestive powers are perfect, provides more chyle, con- 

 ducts into the blood a larger quantity of its proper pabulum. 

 . . . . Their entire vascular system is preternaturally dis- 

 tended. If you open a vein you find that they [persons in a 

 plethoric condition] bear a copious abstraction of blood without 

 fainting, and are even refreshed by it; and the blood drawn 

 separates into a large and firm mass of coagulum, with but little 

 serum. Keeping to the nomenclature we have already employed, 

 we might say that there is here hypertroijhy of the blood." 



The treatment of these cases is sufliciently obvious — abstrac- 

 tion of blood, purgatives, a restricted diet, and increased exercise. 



