50 DISEASE IN WILD MAMMALS AND BIRDS 
register anything resembling the clinical picture of 
angina pectoris in man, and they did not come to their 
death from the arterial changes in the heart alone since 
sufficient other pathology also existed. 
Kinds of Pathological Change. 
As an introduction to the strict pathology of the heart 
it might be well to outline the headings of the scheme 
upon which it seems desirable to study the subject. It is 
hardly profitable to take up seriatim the ordinary general 
pathological processes as discussed in systems of pathol- 
ogy for it is our purpose to show the distribution of basic 
aberrations from the normal in terms of zoological position. 
To this end one must consider the response of the heart 
(a) to damaging influences and (b) to a demand for 
increased work. In the first group come degenerations 
and inflammations, upon which may succeed an incom- 
petency in the form of dilatation. The response of the 
normal heart to any physical demand greater than 
customary has usually been thought to lie in the direction 
of hypertrophy, but on occasion it has seemed to be in the 
form of dilatation, especially if the strain has been sud- 
den and severe. Starling thinks that the primary and 
normal reaction of the heart to physical strain is always 
dilatation. The idea of hypertrophy must not be con- 
fused with an understanding of the relatively large 
hearts in animals whose habits demand great cardiac 
power, for then it is their norm and might be called 
''physiological cardiac hyperplasia." I shall use the 
terms ''increased muscle bulk" and "increased chamber 
space" as preferable to hypertrophy and dilatation; this 
also focuses attention upon the two features of an 
enlarged heart. 
Degenerations and Inflammations. 
Degenerative changes in disease are recorded in our 
system as amyloid, hyaline, fatty metamorphosis, gran- 
ular and cloudy degeneration. "While there is perhaps 
