28 KENNEL DISEASES. 
Causes are said to be predisposing and exciting. While the former are influ- 
ential in increasing the susceptibility to disease, the kind of disease and its 
occurrence are determined only by the latter causes. The term vulnerability is 
used in contradistinction to predisposition. While the latter denotes a tendency 
to a particular form of disease, the former is expressive of a general susceptibil- 
ity to all disease-producing influences. 
The causative influence of age is very considerable. Thus, during early 
puppyhood the stomach is comparatively delicate, and the power of the system 
to resist disease and disease-producing agencies, as exposure, etc., is very low. 
Previous to maturity, inflammatory disorders, with but few exceptions, are most 
liable to occur. The old exhibit increasing debility and infirmity. The common 
tendency is to grow fat and unwieldy. There is then an especial liability to 
fatty degenerations of certain vital organs, and to chronic catarrhal affections. 
DIAGNOSIS AND PROGNOSIS. 
The term diagnosis means the discrimination of diseases; that is, determin- 
ing their character and situation. It is obvious that treatment cannot be success- 
fully employed until their nature and location have been made out, or in other 
words, a diagnosis has been reached. 
A symptom is diagnostic when it occurs more frequently in connection with a 
particular disease than with other diseases. Symptoms are of variable signifi- 
cance. There are a few which are inseparable from a disease, — being found in 
that and no other, — and these are distinguished as pathognomonic. As an 
illustration, a rusty-colored, semi-transparent, and adhesive matter is expelled 
from the air-passages in pneumonia only; and this, therefore, invariably denotes 
the existence of that disease. Some symptoms are said to be highly diagnostic; 
for while not conclusive evidence of particular diseases, they occur in them so 
often that when noted the chances are many that those diseases are present. 
Unfortunately only a very small number of diseases exhibit pathognomonic 
symptoms. Another important fact to be remembered is that all the symptoms 
typical of a disease are but rarely present in a single attack. Some that are 
common to certain diseases may be absent altogether ; others that are not con- 
sidered important are now and then very prominent; and in no small number of 
cases there appear foreign symptoms, that is, symptoms that are not usually 
manifested by, nor indicative of, the existing diseases. All of which, of course, 
tend to mystify and embarrass the investigator, and render diagnoses more diffi- 
cult. Each case therefore must be carefully studied; and a decision should not 
be based on a few individual symptoms merely, but all observed should be duly 
weighed, and conclusions drawn from them as a whole. 
