euros tie | LHistology of Minute Blood-vessels. 205 
Between the cancer germ, which cannot be conveyed by the air 
from the diseased organism to one not infected, and the germ of 
scarlatina, which will retain its vitality for weeks after it has escaped 
from the organism in which it was produced, and may readily gain 
access to healthy organisms in the air they breathe, we have examples 
of living disease germs manifesting powers of retaining their vitality 
when free in many different degrees. In other words, these poisons 
differ remarkably in the facility with which they are propagated, 
or spread from person to person. All exhibit the same appearances, 
though they differ remarkably in power. The capacity for resisting 
death, due to some inherent power and not to their chemical 
composition, varies much, some being capable of living for weeks or 
months away from the fluids of the body, while others die within 
a very short time after their removal from the seat of growth. 
[In this paper a number of remarkable forms of contagious 
matter or virus have been referred to. These resemble one another 
in general appearance. Neither by its form, chemical composition, 
or other demonstrable properties, could the vaccine germ be dis- 
tinguished from the small-pox germ, or the pus germ from either. 
All resemble the minute particles of bioplasm of the blood from 
which they have probably been derived, but from which they differ 
so remarkably in power. Concerning the conditions under which 
these germs are produced, and of the manner in which the rapidly- 
multiplying matter acquires its new and marvellous specific powers, 
we have much to learn, but with vegetable organisms the germs have 
nothing to do. They have originated in man’s organism. Man 
himself has imposed the conditions favourable to their development. 
Man alone is responsible for their origin. Human intelligence, 
energy, and self-sacrifice may succeed in extirpating them, and may 
discover the means of preventing the origin of new forms not now 
in existence. 
IV.—The Histology of Minute Blood-vessels. 
By Brevet Lieut.-Col. Woopwarp, Assist.-Surgeon, U. 8. Army. 
Havine recently been occupied in the critical examination of certain 
preparations, in the Microscopical Section of the Museum, illus- 
trative of the minute anatomy of the blood-vessels, I have thought 
that some of them threw so much light on certain points involved 
in the recent discussions with regard to the doctrine of inflammation, 
that a short account of them would be of interest, and might per- 
haps do good service, in connection with the appreciation of the 
conflicting statements which have appeared in the medical journals 
re, 
