CONSTITUTIONAL DISEASES. 363 



cn its side, will cause the perception by the hand held at 

 a point opposite to this of a sort of wave or thrill, which 

 will render the diagnosis certain. 



Treatment, — The disease is often fatal, but the indica- 

 tions are to cause the absorption of the fluid and to im- 

 prove the general health. 



Unless the patient is very debilitated, purgation by 

 calomel and jalap or elaterium may be tried. 



J^ext, the use of iodide of potassium, or syrup of the 

 iodide of iron, is indicated. Large doses of tincture of 

 iron are also recommended. Digitalis is advocated by 

 some. 



Should the fluid not disappear wdthin two weeks, tap- 

 ping for its removal, which should be very gradual, may 

 be tried. Similar treatment is to be adopted in hydrotho- 

 rax. Treatment for hydrocephalus is generally unavailing. 



Rickets. — Though the most obvious changes are in the 

 bones, the disease is essentially constitutional. 



The bones undergo a series of changes, w^hich result 

 in their becoming enlarged at the ends, less resistant, and 

 consequently more apt to bend, so that deformities are 

 common. 



Of the bones, those of the limbs and head suffer 

 oftenest. Along with this condition of the osseous sys- 

 tem, the whole nutrition of the animal is at fault. Its ap- 

 pearance of general lack of vigor and unthriftiness, sug- 

 gests that the best thing to do with the animal is to chlo- 

 roform it ; and so it is, in many cases. 



Heredity has not been established as a cause — ^i. e., the 



condition has not come to the animal from a rickety 



{rachitic) dam or sire, or one of an otherwise unhealthy 

 25 



