850 ON THE REAL NATURE OF DISEASE GERMS. 
the matter. Nevertheless, what we are able to demonstrate 
is of vast importance, and with the aid of other observations 
and experiments, we may form, 1 think, clear notions of the 
nature and origin of these morbid poisons, and of the manner 
in which they produce their marvellous and oftentimes dis- 
astrous effects. Much yet remains to be disclosed, but we 
shall soon learn more if we will but work and think inde- 
pendently, and accept the teaching of facts of observation 
and experiment, while careful to avoid being misled by the 
dogmatism of those who obstinately persist in asserting that 
all vital phenomena are to be explained by physics and 
chemistry, and try to make people believe that living 
organisms are mere machines constructed by force. All 
truly vital phenomena must necessarily be altogether out of 
the range of mere physical investigation. Nevertheless, to 
such extravagant lengths has the opposite view been carried 
of late, that it has even been seriously stated that he who 
refuses to look upon life as mere inorganic force, opposes 
investigation, and looks upon the structure of man's organism 
as a subject unsuitable for scientific exploration. It would 
be as reasonable to assert that a man who is to be a scientific 
investigator must commence by confessing his belief in the 
truth of a conclusion which has long been proved to be false 
by reason and observation.* 
In spite of all the evidence adduced to the contrary, and 
notwithstanding the failure of all attempts to prove the 
vegetable nature of disease germs, Mr. Simon still adheres 
to this doctrine. He seems to place great reliance upon the 
extraordinary statements of Hallier, which have not been 
confirmed, and ought to be received with the greatest 
caution. In his Report for 1869, Mr. Simon makes the 
following remarks upon this subject: — “ Knowing that all 
contagia (as such) are distinct one from the other, and 
believing that each of them has its essence in the so-called 
microzymes which it contains, we by implication impute to 
the microzymes that in different diseases they are not iden- 
tical ; and as we affirm them to be dynamically different, so 
also we assume that, under well-devised differential experi- 
ments, other signs of their specificity may be brought to 
light, and for each sort of them a definite genesiology be 
* The physical theory of life is, however, less popular now than it was a 
few years ago. Quite recently its strongest advocates have expressed 
themselves more cautiously than has been their custom hitherto. They 
have discovered that the “ tendency of thought ” is fast setting in another 
direction. They have, therefore, modified their statements without with- 
drawing them, and have made preparations for abandoning their position 
without acknowledging defeat. 
