The Microscopie Germ Theory of Disease. By H. G. Bastian, 73 
not tenable witliout the aid of some supplementary hypothesis, I 
cannot conceive that the introduction of the one above mentioned 
will be considered to have strengthened its foundations. Yet Dr. 
Sanderson apparently savs^ the difficulty of maintaining the germ 
theory in its integrity, and offered us this other view as a com- 
promise. He considers it probable that, whereas true contagia, 
whether Hving particles or chemical compounds, may be engendered 
within the body in the tissues themselves, such contagia are not 
able to spread either within or outside without the aid of bacteria 
to act as "carriers." But why one set of particles should need 
others to carry them, or why bacteria alone should be able to bear 
about these mysterious contagious poisons which they are devoid of 
the power of originating, does not at all appear ! 
However complicated the doctrine may have been rendered, 
this is still practically the germ theory ; and the same thing may 
be said with reference to a view which Professor Lister seems to 
entertain with some favour. He thinks that the lower fungi and 
their relations bacteria may contain within themselves some chemical 
compound absolutely peculiar to them, and forming part of their 
substance, which may act upon albuminous compounds after the 
manoer of a ferment, such as emulsin.* "In this sense," he 
thinks, " as intervening between the growth of the organisms and 
the resulting decompositions, the theory of chemical ferments might 
be welcomed as a valuable hypothesis." This seems like the lan- 
guage of concession, but, practically, it is the germ theory still, and 
expressed too much, as all germ theorists who think out their views 
would have to formulate them. It would be no great concession 
to those who are not believers in an exclusive germ theory if, in 
the light of his views as above expressed. Professor Lister were to 
say that bacteria were " carriers of infection " ; yet the apparent 
concession above referred to is no more of a concession to be- 
lievers in a physico-chemical theory than the latter admission 
would be. 
I will, however, now briefly enumerate the evidence which 
seems to me quite sufficient to disprove the probability of the 
existence of any causal relationship between the lower organisms 
and the diseases cited at the head of this section, and to establish, 
on the other hand, the position that the bacteria met with in 
diseased fluids and tissues are for the most part actual pathological 
products — that they are, in fact, engendered within the body, or 
are descendants of organisms owning such an origin, rather than 
of previously existing organisms introduced from without. It 
would take far too long were I to attempt to enter at any length 
upon a consideration of this evidence. I must therefore content 
* ' Nature,' July 17, 1873. 
