The Microscopic Germ Theory of Disease. By II. C. Bastian. 139 
processes are not so similar as they have been supposed, we may 
now more readily recognize since the processes of fermentation 
occurring in vegetal tissues have been investigated. The relation- 
ship existing between zymosis and these modified processes of fer- 
mentation taking place in fruits and tubers seems, indeed, far more 
close than that between the zymotic processes in animals and ordi- 
nary kinds of fermentation. 
In the process occurring in vegetal tissues, as well as in those 
morbid processes which take place in the animal organism, the pre- 
sence of rapidly multiplying independent organisms is an occasional 
rather than a necessary feature. Though usually absent in other 
allied processes, yet we find organisms invariably manifest them- 
selves throughout the tissues of beet-root and of the potato, when 
these are placed under certain abnormal (“ unhygienic ”) conditions. 
And though usually absent from the blood of persons suffering from 
specific contagious fevers, yet do we also find organisms invariably 
showing themselves in the blood of persons suffering from some of 
them, such as relapsing fever and splenic fever. Nay, further, 
under the influence of a “ change of conditions ” alone we may 
initiate these modified fermentative processes in vegetables ; that is 
to say, in ordinary parlance, the processes may originate “ sponta- 
neously ” or de novo. But if the modified activity of tissue-elements 
suffices to initiate such morbid processes in the vegetal organism, 
why may it not occasionally do the same in the animal organism ? 
This is a point of view which seems too valuable to be lost sight 
of, more especially in the face of the results yielded by our flask 
experiments. 
3. In conclusion, I would maintain that the facts already known 
abundantly suffice to displace the narrow and exclusive vital theory, 
and to re-establish a broader physico-chemical theory of fermen- 
tation. 
Whether the “ ferment ” in any given case be an independent 
living organism, a tissue-element, a fragment of not-living organic 
matter, or some mere physico-chemical influence (as in the case of 
the action of finely divided platinum), the initiated fermentative 
change is in each case a result of chemical action. And similarly 
with regard to “ contagium,” whether it be an altered though living 
tissue-element, a fragment of dead organic matter, a chemical com- 
pound (or even the more vague influence of a “ set of conditions ” 
which may suffice to generate contagium de novo), we have in each 
case to do with gradually initiated chemical changes, distinctive in 
kind and gradually terminating in one or other of the recognized 
varieties of zymotic affections. The changes in each case where 
we happen to have to do with living ferments or living contagia 
would be due only to an infinitesimal extent to the organic multi- 
plication of such living units, though the decompositions set up by 
