Hypertrophy of the Heart. 431 



Birds. Causes of hypertrophy. The condition is said to be 

 common in pigeons and has been attributed to natural timidity, 

 excessive emotion and sudden excited movements (Cadeac). 



Symptoms. In simple hypertrophy the heart beats are more 

 forcible and prolonged so that the period of silence or rest is 

 shortened. This is due to the greater length of time taken up in 

 the contraction of the ventricles. For the same reason the pulse 

 which may or may not be accelerated, irregular or intermittent, is 

 full and rolling or as it were prolonged. The first sound of the 

 heart is prolonged and low or muffled, sometimes almost inaudible 

 while the second is unnaturally loud. Sometimes when one ven- 

 tricle only is enlarged that may complete its contraction later than 

 the other and the second sound is repeated as in the syllables 

 lub — tip tip. A duplication of the first sound only is less com- 

 mon. If the sounds are heard over a greater extent of the chest's 

 surface than is natural, the lungs being healthy, it is probably 

 due to h3^ertrophy of the heart. If very clear on the right side 

 they indicate increase of the right ventricle. The heart's im- 

 pulse is usually strong and may be felt on both sides, and it may 

 be over the whole chest. 



Percussion usually shows a more extended dullness in the 

 region of the heart but the blows must be pretty forcible to bring 

 out the deeper resonance, otherwise it will come only from the 

 thin layer of lung. These results are of the greatest value in 

 the dog. 



The pulse is usually regular and if excited to irregularity and 

 intermission quickly returns to its natural state when the patient 

 is left at rest. 



As hypertrophy is usually associated with dilatation of the 

 heart, the following table will prove valuable by presenting side 

 by side the signs indicating hypertrophy with and without dilata- 

 tion, and simple dilatation. • 



