CAUSATION. 293 



The greater number of animal sufferers from this affection are 

 those which, immediately antecedent to their giving evidence 

 of this condition, have passed through some constitutional and 

 debilitating disease. 



The entire functional activities of the animal are below par ; 

 the system is yet charged with, or at least not entirely rid of, 

 effete and deleterious matters, the result of morbid and excessive 

 tissue-changes produced during previous diseased action. If by 

 any means, operating from without, the vital energies be further 

 lowered, or the deleterious materials circulating in the blood 

 be prevented from being eliminated, we can so far comprehend 

 that the extrinsic influences acting in concert with those exist- 

 ing within will most probably culminate in the production of 

 an unhealthy and vitiated state of the blood, and consequently 

 of every other tissue. Why this depraved condition of the 

 blood should show itself in this particular and distinctive 

 manner, and not in some others, we may not be able to tell. 

 With our present knowledge, we must probably accept this as 

 an ultimate fact until better able to explain many other pro- 

 cesses, healthy as well as diseased. 



In all cases of convalescence from disease, particularly 

 general diseases of a lowering character, it is absolutely neces- 

 sary, if we would reduce to the minimum the risk of the occur- 

 rence of this and other obscure — obscure, I mean, in the sense 

 of their aetiology — blood diseases, that we give particular atten- 

 tion to the enforcement of correct sanitary conditions, and a 

 carefully regulated diet. If the disease is not propagated by 

 contagion we ought to see if its occurrence cannot be limited 

 by correct hygiene. From my own experience I do not know, 

 certainly, that there are any indications whereby we may know 

 that any particular animal, recovering from such diseases as 

 strangles, catarrh, or distemper, is likely to develop scarlatina. 

 It is seen in cases of recovery from mild as well as from severe 

 attacks ; it is encountered in young and in old animals, and in 

 coarse as in Avell-bred horses. 



c. Anatomical Characters. — The structural and tissue 

 changes cognizable to the naked eye, in such cases of scarlatina 

 as terminate fatally, are somewhat similar to those observed 

 in some other blood diseases. The blood is darker as a whole 

 than natural, and of greater fluidity ; it is also changed in its 



