186 ANATOMY OF DISEASES 



when under circumstances of unusual excitation, beats violently against the 

 ribs, and, were it not thus tied down, would often bruise and injure itself, 

 and cause inflammation in the neighbouring parts. 



The heart is composed of four cavities ; two above, called auricles, 

 from their shape and two below, termed ventricles, occupying the bulk of 

 the heart. In point of fact, there are two hearts the one on the left side 

 propelling the blood through the frame, and the other on the right side 

 conveying it through the pulmonary system ; but, united in the manner in 

 which they are, their junction contributes to their mutual strength, and 

 both circulations are carried on at the same time. 



The beating of the heart in the dog is best examined behind the elbow 

 on the left side. The hand, applied flat against the ribs, will give the 

 number and character of the pulsations. The pericardium, or outer invest- 

 ing membrane of the heart, is frequently liable to inflammation, indicated 

 by a quickened and irregular respiration, and an action of the heart, bound- 

 ing at an early period of the disease, but becoming scarcely recognisable as 

 the fluid increases. The patient is then beginning gradually to sink. A 

 thickening of the substance of the heart is occasionally suspected, and, on 

 the other hand, an increased capacity of the cavities of the heart ; the 

 parietes being considerably thinner, and the frame of the animal emaciated. 



The pulse of the greater part of our domestic animals has been calcu- 

 lated by Mr. Vatel, in his excellent work on Veterinary Pathology, to be 

 nearly as follows : 



38 pulsations in a minute. 



The pulse of the dog maybe easily ascertained by feeling at the heart or 

 the inside of the knee, and it varies materially, according to the breed, as 

 well as the size of the animal. This is very strikingly the case with some 

 of the sporting dogs, with whom the force as well as the rapidity of the 

 pulse vary materially according to the character and breed of the dog. 



There is, occasionally, in the dog as in the human being, an alteration of 

 the quantity, as well as of the quality, of the blood. An&mia is the term 

 used to designate a deficiency in quantity ; plethora the opposite state of it, 

 M. D' Arbor relates a very curious account of the former : 



Two dogs were sent into the hospital of the veterinary school at Lyons. 

 They did not appear to suffer any considerable pain. Their skin and 

 mucous membranes that were visible had a peculiar appearance. They 

 had also comparatively little power over their limbs ; so little, indeed, that 

 they rested continually on one side, without the ability to shift their posture. 

 When they were placed on their feet, their limbs gave way, and they fell 

 the moment they were quitted. In despite of the care that was taken of 

 them they died on the second day. 



