32 CLINICAL DIAGNOSTICS. 



nant animals caution is demanded in the choice of drug's. 



III. Color and white markings. For diagnosis the 

 color and markings arc of less importance. White horses fre- 

 quently suffer from melanotic tumors that are either super- 

 ficial or located in internal organs. White areas are more pre- 

 disposed to exanthemas, sunburn and. "scratches." 



IV. Age. Many diseases -occur either exclusively or 

 generally in youth. Rachitis, diseases of the navel, strangles 

 in colts, scours in calves and distemper in puppies are exam- 

 ples. In old individuals diseases due to the animal's use are 

 more frequent as are also chronic diseases of organs (dummies, 

 heaves). 



The age is also of influence upon the prognosis in as much 

 as healing, all things else being equal, is more to be hoped for 

 in the young individual than in the old one. In old animals 

 where the prognosis is a doubtful one all treatment is fre- 

 quently omitted on economic grounds. 



V. Size. Size is of importance in posology only. 



VI. Breed. In well bred animals the reaction against 

 the encroachment of disease is more energetic and the symp- 

 toms are more pronounced. Certain breeds are more able to 

 withstand infectious and sporadic diseases than others, this 

 must be considered in making a prognosis. Breed is also 

 taken into consideration in the treatment of diseases. Well 

 bred, fine skinned, sensitive horses yield to the action of cer- 

 tain drugs more readily than those of the opposite type. This 

 is especially true where outward applications (turpentine blis- 

 ters) are to be made. 



2. Habitus. 



By the term habitus we mean the general or external as- 

 pect or characteristic appearance of the patient, which is de- 

 termined by its physical attitude, condition, conformation and 

 temperament. It offers a convenient aid in diagnosis, one 

 that can be readily observed and that, in many respects, is of 



