DISEASES OP THE BLOOD. 99 



position to disorder. Such is the case when excretory 

 organs act inefficiently, or when excessive material is 

 added. These states are, therefore, generally purely of a 

 secondary character. The cause being removed they will 

 cease. Decrease of these normal constituents may be 

 similarly of minor importance. We have seen that fibrin 

 is increased in fevers, especially those due to considerable 

 local inflammation. It seems this is associated with disin- 

 tegration of corpuscles ; hence we find products of a 

 highly plastic character generated under these circum- 

 stances. In ansemia the fibrin factors are deficient, the 

 blood and deposits wanting in plasticity. Though occur- 

 ring frequently in disease, variations of amount of fibrin 

 factors have not been proved to constitute distinct 

 disorder. 



Leucaemia, oe Leucocyth^mia, results from excessive 

 production of white corpuscles in consequence of the 

 activity of the spleen, lymphatic glands, and medulla of 

 bone, these being the blood-making organs. The spleen 

 and lymphatic glands undergo enlargement and become 

 altered in appearance. The white globules of the blood, 

 instead of being in the proportion of one to three or four 

 hundred, are as one to thirty or forty. This disease has 

 been described by Siedamgrotzky ('Veterinarian,^ 1880, 

 p. 159). He mentions it as occurring in cattle, females 

 being most subject. The symptoms are those of 

 anaamia. 



The red corpuscles we have seen are largely increased 

 in plethora, and they may be more numerous in fevers ; 

 evidence is rather uncertain on this point. This simply 

 gives rise to increased functional energy ; indeed, in 

 health the improvement of a breed and high feeding 

 increase the number of these elements. *' Free exposure 

 to fresh air and light seems also to powerfully promote 

 the formation of red blood as much as the deprivation of 

 them tends to destroy it " (Jones). From this we deduce 

 a practical indication for treatment of anasmia. When 

 the destruction of red corpuscles predominates over their 

 formation poverty of the blood results. Mercury seems 



