VALVULAR DISEASE. 67 
to atrophy, calcareous degeneration, or calcareous or fibrinous deposits on the 
lining membrane. 
The difficulties in the way of detection of heart-disease with near certainty 
are great, for the evidence is mainly in the heart-sounds; and only a very slight 
modification may be positive proof of a fatal malady. The ear, therefore, must 
be relied upon in making a diagnosis, and it must necessarily be very highly 
trained. In man one sound is fairly sharp and distinct; the other is compara- 
tively dull and prolonged. First provided with a good anatomical and physio- 
logical knowledge of the heart, and afforded abundant material and opportunity 
to listen to and study different hearts in healthy men, one after a time becomes 
able to detect abnormalities in the sounds and draw right conclusions ; but such 
advance is slow, tedious and far from easy. Yet the study of the heart of dogs 
is attended with far greater difficulties than that of man, for in the former, even 
during perfect health, the sounds are indistinct and incomplete. It cannot, 
therefore, be encouraged, or this discussion be rightly more than a brief and 
passing notice. 
VALVULAR DISEASE. 
Inflammation of the heart affects chiefly either its lining membrane or the 
membrane that covers it, to which allusion has been made, called the pericardium. 
The former is termed endocarditis and the latter pericarditis. Both forms of 
heart inflammation occur most often during acute inflammatory rheumatism. En- 
docarditis generally affects the valves of the left side of the heart; and one or 
both of them may be so distorted that they either do not close perfectly or the 
openings they control become contracted. In consequence of imperfect closure 
of a valve, more or less of the blood that has passed through it flows back; while 
a contraction of an orifice retards the passage of blood. Such defects interfere 
with circulation, and to compensate for them the heart must work harder or 
. faster, or both. As a result it first undergoes hypertrophy; and after the limit 
of that change has been reached, the walls of the organ become dilated, and con- 
sequently weakened. In the meantime the entire organism is more or less dis- 
turbed by the cardiac abnormality, although it may exist for a long time without 
causing grave symptoms. 
Endocarditis is now believed by many to be of germ origin, one or more germs 
being invariably accountable for its production. 
When following inflammatory rheumatism, valvular changes may begin within 
a few months and progress quite rapidly ; but, as a rule, it is not until several years 
after the rheumatic attack that little growths, somewhat like warts, spring up from 
the lining membrane on or near the valves, or the openings they guard commence 
tonarrow. These changes well advanced, the symptoms induced are unduly quick- 
