Diseases of the Heart and Organs of Circulation. 409 



tervals there is a complete pause extending over that period of 

 time which would have been occupied by a full beat ; unequal 

 when some beats are strong and others weak ; irregular when 

 without any distinct intermission for a period equal to that of a 

 single beat, the intervals between successive beats are of varying 

 length. The pulse further has a peculiar thrill or tremor in 

 states of great debility with deficiency of blood and imperfect 

 filling of the vessels. 



Of these the leaping, the intermittent, the unequal and the 

 irregular pulses are of special importance in their bearing on 

 heart diseases. 



The jerking and receding pulse is felt in cases of imperfection 

 of the semi-lunar valves at the commencement of the great aorta, 

 and which allows blood propelled into the arteries by the contrac- 

 tion of the ventricle to flow back into the ventricle during its state 

 of relaxation. This pulse is met with in other conditions as in 

 aneurism of the aorta, but if from heart disease it is distinguished 

 by the presence of a blowing murmur with the second sound of 

 the heart. 



The intermittent pulse indicates functional derangement of the 

 heart but it does not as is generally believed betoken structural 

 disease. It is frequently observed in healthy asses and mules, 

 and ir dogs however slightly excited whether by fear or joy, or 

 by the mere fact of their being handled, it is so common as to be 

 almost the rule rather than the exception. It may be seen in a 

 healthy horse as the result of excitement. During the early 

 stages of convalesence from inflammatory affections of the lungs 

 in the horse the pulse is often intermittent. The pulsations are 

 at the same tinie unequal. There is a regular cycle of beats grad- 

 ually decreasing in force and extending over a complete respira- 

 tory act. The cycle commences with the strongest beat during or 

 immediately after the act of expiration, and the succeeding four 

 or five beats are less and less forcible until the chest is fully ex- 

 panded when there is a quiescent interval corresponding to the 

 period of one beat. In many such cases there is no other indica- 

 tion of heart disease and the phenomenon appears due to the in- 

 terference with the circulation by the hepatized lung, to the im- 

 paired nervous energy of the heart and to its compression between 

 the distended lungs. A pulse simply intermittent and not assoc- 



