GENERAL SYMPTOMS OF DISEASE. 39 



Tlte double pulse. — This pulse is occasionally present in 

 hsemo-albuminuria (red water) in cows, and in purpura in the 

 horse. It denotes, according to Dr. Sanderson, that condition 

 of the circulation in which arterial pressure is diminished, while 

 the venous is increased, and that the capillary current, instead of 

 being constant in its rate of movement, is markedly accelerated 

 during the diastole, and retarded during the diastolic interval. 

 In the undulatory double pulse of typhus, says Dr. Sanderson, the 

 intensity and suddenness of the second expansion appears nearly 

 as great as the first; the explanation being, that in this con- 

 dition the contractions of the heart are extremely feeble, the 

 arterial pressure being so low that the progressive movement of 

 the blood ceases entirely in tlie capillaries during the diastolic 

 interval. 



Tlie strength of the pulse depends chiefly upon the force with 

 wliich the ventricles contract ; in some measure upon the tonicity 

 of the arteries, and upon the volume of the blood. In order to have 

 a strong pulse there must be vigour of impulse, steady resistance 

 to pressure, and a certain degree of fulness. There may be a 

 sharp, forcible beat ; but if this is not sustained by a certain 

 amount of subsequent pressure, it indicates irritation rather 

 than energy. A very contracted pulse, however sharp the 

 impulse, cannot be called a strong one. A strong pulse is 

 considered a sign of a sthenic or vigorous state of the system. 

 But it is not invariably so, for hypertrophy of the heart will 

 give strength to the pulse, even though the general powers 

 of the animal be weak. 



Weakness of the pulse. — In order to have a weak pulse it is 

 essential that the impulse be slight, the tonicity of the arteries 

 diminished, and the volume small. In some cases, however, it 

 will be found, if there be a slow action of the heart, or great 

 relaxation of the arterial coats, that there will be a full, and at 

 the same time a feeble pulse. It is important not to confound 

 this with strength. 



The venous pulse. — Pulsation of the veins is often seen in 

 the jugulars of the ox, especially during rumination, and 

 seems to be quite compatible with health. If the head or neck 

 of the horse be extended, there wiU generally be an appearance 

 of a jugular pulse. This, however, arises from the beating of the 

 carotids, which is made visible by the parts being tensely 



