CHAPTER XI. 
DISEASES OF THE CIRCULATORY SYSTEM. 
Heart and Larger Blood Vessels. 
Diseases of the heart as evidenced by post-mortem examinations 
are much more common than might be supposed. The diagnosis 
of such during life, however, much less the differentiation of one 
condition from another, is surrounded by difficulties. The position 
of the heart, coupled with the extreme suspicion and nervousness 
•displayed by most elephants on the approach of any stranger, renders 
efforts at examination difficult and unsatisfactory. Post-mortem 
examination sometimes reveals that heart-disease in an advanced 
stage may exist without being suspected during life. 
Symptoms pointing to heart affections are alterations in the 
character of the pulse, which may be regularly or irregularly inter- 
mittent ; i.e.^ in the former case, a pause or miss of a beat is observed 
at regular intervals, say after every fifth or tenth beat ; in the latter, 
the pause occurs at irregular intervals. The pulse may be accele- 
rated and in some instances retarded ; breathlessness (the mucous 
membranes being of a bluish colour) more apparent when an animal 
is put to work, or rapid exhaustion, muscular weakness, giddiness 
or fainting shortly after ; coldness of the extremities, the presence 
of dropsical swellings about the body, limbs, etc. ; in fact conditions 
pointing to defective circulation, such as sloughing of portions of 
the ears and tail, gradually increasing weakness and emaciation, 
and finally sudden death not attributable to other causes. In 
elephants death may occur suddenly from long continued and 
unobserved disease of the heart. It must not be forgotten that 
functional troubles may give rise to many of these symptoms ; hence 
careful observation for some time is necessary to avoid as much as 
possible drawing hasty conclusions and thus making very serious 
errors, such as disposing of a valuable animal which may be 
considered useless, and finding later on the symptoms have dis- 
appeared and that the animal is working as usual. 
Causes.- — The chief factor in bringing about disease of the heart 
and vessels is overstrain from continued or even sudden over- 
exertion. It is only necessary to see animals working heavy 
timber in difficult places to estimate the enormous physical exertion 
required to perform the tasks they do. 
