132 W. L. WILLIAMS. 
Various other pathologists hold yet other views as to the 
meaning of these words, and among these there is, according 
to Dr. Schwartzkopff a group (to which he apparently belongs) 
who apply the term infectious to those diseases in which “ the ! 
micro-organism has its natural origin outside the animal body 
on vegetable life.” By such a classification apparently, Dr 
Schwartzkopff holds that actinomycosis, for instance, is not! 
contagious but merely infectious, and that the actinomyces 
originate outside the animal body on vegetable life. The 
proof of such a genealogy for actinomyces apparently rests 
upon the fact that the germ was studied for years as affect 
ing the animal body before it was found on vegetation, anc 
it still exists in a more luxuriant form in the animal than or 
plants. 
Being by the admission of Dr. Schwartzkopff transmissible 
from animal to animal, the disease was contagions when known 
in animals only, and became infectious when found some years 
later growing very scantily on vegetation. But a large pro?: 
portion of known pathogenic organisms are artificially culti¬ 
vated in vegetable media, and we at present have no means 
of knowing but that they were originally derived from vege-: 
tation, consequently such a classification would prove vacilla¬ 
ting, and the line separating the two would waver to and fre 
as the weight of evidence at a given epoch favored an origi¬ 
nal animal or vegetable habitat, and could never be definitely 
settled until new means are discovered for determining 
whether in a given disease the pathogenic germ was derived 
by animals from vegetation ; or, on the other hand if the patho¬ 
genic germ found on vegetation was derived from animals. 
Priority 7 of source of discovery by man, or complexity of de¬ 
velopment, cannot suffice to positively indicate the primitive 
habitat. 
Consequently we see utter confusion in the various at¬ 
tempts to put a definite meaning on these terms satisfactory 
to all. If, however, one will at the outset define the terms 
which he proposes to use, his definition must necessarily suf¬ 
fice for his contribution, and critics are in duty bound tej 
accept such definition in subsequent portions of the given ar- 
