34 PATHOLOGY. 



the other a pulse of forty-five per minute, and both may be in a 

 state of most perfect health ; but a difference beyond this indi- 

 cates some degree of excitement, or some amount of disease. 



A frequent pulse — say a pulse above fifty-five per minute — if 

 the horse is not in an excited state, from exercise or other 

 accountable or natural cause, indicates a fevered condition, but 

 not necessarily an increased vigour of the system ; on the contrary, 

 a very frequent pulse is generally associated with extreme pro- 

 stration and debility, A certain quantity of blood is requisite 

 to the existence of the several parts of the body ; and when the 

 heart is too feeble to act forcibly, it is compelled to excessive 

 frequency of contraction to compensate for such want of strength. 

 Excessive evacuations either of blood or of any of the secretions 

 are generally attended with frequency of the pulse. 



The old belief that " bleeding lowered the action of the heart 

 and arteries," is disproved by the fact that all evacuations in- 

 crease the number of the pulsations. I have repeatedly observed 

 the effects of bleeding upon a healthy animal, and found that 

 when from three to five quarts of blood have been withdrawn, 

 the pulse has increased in frequency ten to twenty beats per 

 minute ; when the bleeding has been pushed beyond this, say to 

 the extent of from seven to ten quarts, the pulsations have risen 

 to extreme frequency — to 100, 120, or more per minute. As the 

 pulse increases in frequency it becomes diminished in volume, 

 supporting the conclusion that a pulse is smaU in proportion to 

 its frequency. 



The quick pulse — -pulsus cclcr. — This term is made use of to 

 denote that condition of the circulation in which the heart 

 accomplishes its contraction almost instantaneously. The terms 

 quick and slow have been objected to by Sir Thos Watson, as 

 over-refinements, " simply because it was not certain what was 

 meant by the terms by those writers who used them," and that 

 it was very doubtful whether the quality of quickness or celerity 

 of each pulsation could be truly appreciated by the finger. But 

 the terms are now revived, for the quahties which they express 

 are made manifest by the use of the sphygmograph, an instru- 

 ment by which the movements of the artery are transferred to 

 paper, in such a manner as to render it possible to measure their 

 extent and relative duration. — (See Dr. Buedon Sanderson's 

 Haiidhook of the Sphygmograjph.) 



