1889.] Etiological Classification of Diseases. 961 
infectious diseases, but they are vastly different in point of 
origin, the one originating in and from infected earth, the other in 
and from a diseased individual. The source of primary origin 
alone decides this question. Accidental or experimental extension 
has nothing whatever to do with it. 
But take another case which at the outset looks somewhat 
complicated. An ox is confined in a stable ; it becomes diseased 
with anthrax ; a fly stings it and then lights on the attendant and 
bites him ; the man dies of malignant pustule. In this case the 
diseased ox was " contagious" to the fly and the latter to the man, 
but is anthrax a contagious disease ? By no means ; the fly was 
the accidental transmitter, the living syringe which filled itself 
from the blood of the ox and then introduced the infection to the 
man by its needle-like proboscis. The ox, however, became pri- 
marily infected from some source having no connection with 
animal life. 
These statements of the case as to " contagion " and " contagi- 
ousness " should settle the question in every logical mind. 
Remember, transmissibility of an inficiens either artificially or 
accidentally has nothing to do with the differention of infectious 
diseases as to class. The locus of primary origin and continuous 
natural development can alone decide as to whether a given 
disease is exogenous or endogenous in character. 
Let us return to the question of the pathogenic nature of ac- 
tinomycosis again for a moment. Actinomycosis is not an in- 
fectious disease in any true sense of the word, every authority to 
the contrary notwithstanding. An infectious disease, be it ex- 
ogenous or endogenous in character, is one which is invariably 
accompanied at some time in its course by one general symptom, 
— fever, which is an invariable symptom of general or constitu- 
tional disturbance. The very word infection means that some- 
thing has been produced which is of a general polluting character 
to the infected organism. Nothing of this kind occurs in actino- 
niycosis per se. There is not necessarily any fever in this disease. 
Actinomycosis is always local, never general. Unless the disturb- 
ances are of such a character, or so situated, as to mechanically 
interfere with the functions of the organism, the individual does not 
