438 Veterinary Medicine. 



trophy, and hence the frequent co-existence of the two. Pure 

 dilatation occurs especially when internal pressure takes place 

 suddenly and to excess, and while the nutritive functions are to 

 a great extent in abeyance. Such conditions are found in acute 

 inflammations of the respiratory organs, or of the inner or outer 

 membranes of the heart, and the rapid deposit in the lungs of 

 tubercles or other abnormal material. 



Dilatation of the right side of the heart is a common complaint 

 in overfed cattle, and is apparently due to the diminished power 

 of resistance in the walls of the heart, the muscular substance of 

 which is partly replaced bv fatty granules, and to the obstruction 

 offered to the circulation by the extraordinary accumulation of 

 fat around the base of the heart and the commencement of the 

 large blood vessels. Though a diseased condition, this rarely 

 shortens life or interferes with the uses to which cattle are put. 

 Pulmonary tuberculosis is a common cause, the blood being 

 forced back on the right ventricle. 



Chronic bronchitis or pneumonia. The heart walls are sim- 

 ilarly weakened and yield moire readily to the internal blood 

 pressure in endocarditis, myocarditis, pericarditis, high fever, 

 infectious diseases, poisonings, anaemia, and debilitating diseases 

 generally. Debility, degeneration and incapacity to resist the 

 blood pressure is the essential prerequisite to dilatation. Old 

 age is a common factor in dogs. 



The symptoms which have been already enumerated in the 

 table given under the head of hypertrophy are mainly these : 

 l/oss of appetite, spirit and endurance ; faintness and difficulty 

 of breathing on the slightest exertion ; habitual coldness with a 

 tendency to dropsy of the extremities ; ascites ; hydrothorax ; 

 loss of control over the extremities when walked or trotted far ; 

 venous pulsation in the jugulars ; heart's impulse weak and un- 

 dulatory or tremulous, or under exertion tumultuous or palpitat- 

 ing ; murmur often present with the first sound ; the first or more 

 commonly the second sound may be doubled ; pulse small, weak, 

 irregular, and often intermittent, and frequently livid spots in 

 the nasal mucous membrane. Paroxysms of unsteady gait from 

 irregular circulation in the brain are frequent, and Dyer asserts 

 that he has repeatedly seen blindness as a result of this condition. 



In treatment the main purpose should be to put a stop to the 



