The Microscopic Germ Theory of Disease. By II. C. Bastian. 137 
organisms taking place in the skin in connection with its charac- 
teristic pustules ; whilst in typhoid fever we have also an active 
growth of rather different organisms in the substance of the ileum, 
and more especially in the tissues constituting Peyer’s patches — 
that is, in connection with the anatomical marks of this disease * But 
just as a mere chemical irritant (ammonia) injected beneath the skin 
of a rabbit produces, as Dr. Sanderson tells us, a local inflammation 
in which the fluids effused swarm with bacteria, why may not the 
morbid processes taking place within the skin in small-pox engen- 
der irritants which may lead to the appearance of somewhat similar 
products ? So that, in the face of the evidence already detailed 
concerning the occurrence of heterogenesis, the presence of organ- 
isms in connection with small-pox lesions may be readily accounted 
for, without the necessity of attaching any very important role to 
them. And as regards the presence of organisms in Peyer’s 
patches and adjacent parts, in cases of typhoid fever, no greater 
importance could be accorded to this association by any but enthu- 
siastic germ theorists. For, even if the reasons above alluded to 
were not very influential with them, there is another mode of 
looking at the matter, from quite an orthodox point of view, which 
would equally assign to the local development of organisms a very 
subordinate role. Morbid tissues are generally admitted to form a 
favourable nidus for fungoid growths, and the intestine is known 
to contain the germs or spores of such bodies. The flourishing 
growth of leptothrix and fungi in the diseased mucous membrane 
may therefore be only another example of an already well-known 
class of effects ; so that, looking at the question from all sides, it 
seems to me, in the present state of our knowledge, to be extremely 
improbable that these newly discovered organisms have any causal 
relationship to typhoid fever. 
It only remains for me now to make a few very brief concluding 
observations concerning — (1) Pasteur’s recent important modifica- 
tions of his germ theory of fermentation ; (2) upon the degree of 
relationship existing between fermentation and zymosis ; and (3) as 
to the probable mode of action of ferments and contagia. 
1 . Pasteur has within the last two years made a most important 
modification in his theory of fermentation.! Whilst he formerly 
held that fermentations and putrefactions are chemical processes 
initiated by independent organisms (bacteria and their allies), and 
taking place in correlation with their growth and multiplication, he 
has of late shown that similar phenomena may be initiated by the 
chemical processes taking place in the tissue-elements of certain 
fruits and vegetable tissues, when these are placed under certain 
* ‘British Medical Journal,’ December 5, 1871. 
f ' Compt. Rend.,’ 1873-4. 
