130 The Microscopic Germ Theory of Disease, By H. C. Bastian. 
either case where organisms are found this fact alone would give 
us no right to infer that they had developed from pre-existing 
germs (in the natural history sense of that term) ; they may, on 
the contrary, have arisen either by heterogenesis or by archebiosis. 
The weight of probability in favour of either of these two 
possibiHties can only be judged of by resort to a different method 
of procedure. Because in view of the observed absence of bacteria 
from the tissues of such organs as kidney, liver, or brain, imme- 
diately after death, the subsequent multitudinous presence of 
organisms in these situations would, in the face of satisfactory 
independent evidence, be more easily accounted for by heterogenesis 
or archebiosis than by the hypothesis of pre-existing latent or 
potential germs. By an appeal to evidence of this kind, moreover, 
we are enabled to test the probability of the hypothesis previously 
referred to as being supported by Dr. Beale and others — viz. that 
which assumes the existence of invisible and mysteriously derived 
germs of bacteria and fungi throughout the elements of the tissues — 
an hypothesis somewhat wild in character, which has, I believe, 
no other foundation than the frequently observed prevalence of 
organisms in some of these situations. 
With the view of settling these questions, therefore, we may care- 
fully prepare an infusion from some animal tissue, be it muscle, 
kidney, or liver ; we may place it in a flask whose neck is drawn 
out and narrowed in the blow-pipe flame ; we may boil the fluid, 
seal the vessel during ebullition, and, keeping it in a warm place, 
may await the result as I have so often done. After a variable 
time the previously heated fluid within the hermetically sealed 
flask swarms more or less plentifully with bacteria and allied or- 
ganisms, even though the fluids have been so much degraded in 
quahty by exposure to this high temperature, and have thereby, 
in all probability, been rendered far less prone to engender inde- 
pendent living units than the unheated fluids in the tissues would 
be. We operate, however, under these disadvantageous conditions 
in order to make thoroughly sure that, by the preKminary heating, 
we have destroyed all pre-existing life within the flask ; and, not- 
withstanding such adverse circumstances, we are able to obtain 
evidence of the occurrence of archebiosis. The researches of 
Kiihne and others have fully shown that the protoplasm entering 
into the composition of the tissues of warm-blooded animals is 
coagulated and killed at a temperature of about 111° F. ; whilst my 
own investigations * also show that bacteria and allied organisms are 
killed by exposure in the moist state to a temperature of 140° F. 
Hence I contend that the wide distribution of bacteria through- 
out the human body in connection with dying tissue-elements in 
* ' Evolution and the Origin of Life,' 1874, p. 101. 
