ATMOSPHERE IN RELATION TO PUTREE ACTION AND INFECTION. 
47 
has been exposed to the air, but on which no trace of a Bacterium is to be found’ 
will in two or three days develop in it a multitudinous crop of life. 
We have now to look a little more closely at these particles, foreign to the atmo- 
sphere but floating in it, and proved beyond doubt to be the origin of all the Bacterial 
life which our experiments have thus far revealed. We must also look at them as they 
exist in water, in countless multitudes, being as foreign to this medium as the floating 
atmospheric dust is to the air in which it swims. The existence of the particles is quite 
as certain as if they could be felt between the fingers, or seen by the naked eye. 
Supposing them to augment in magnitude until they come, not only within range of the 
microscope, but within range of the unaided senses. Let it be assumed that our know- 
ledge of them under these circumstances remains as defective as it is now — that we 
do not know whether they are germs, particles of dead organic dust, or particles of 
mineral matter. Suppose a vessel (say a flower-pot) to be at hand filled with nutri- 
tious earth, with which we mix our unknown particles, and that in forty-eight hours 
subsequently buds and blades of well-defined cresses and grasses appear above the 
soil. Suppose the experiment when repeated a hundred times to yield the same un- 
varying result. What would be our conclusion'? Should we regard those living 
plants as the product of dead dust, of mineral particles ? or should we regard them as 
the offspring of living seeds? The reply is unavoidable. We should undoubtedly con- 
sider the experiment with the flower-pot as clearing up our preexisting ignorance ; we 
should regard the fact of their producing cresses and grasses as proof positive that the 
particles sown in the earth of the pot were the seeds of the plants which have grown 
from them. It would be simply monstrous to conclude that they had been “ spon- 
taneously generated.” 
This reasoning applies word for word to the development of Bacteria from that floating 
matter which the electric beam reveals in the air, and in the absence of which no Bac- 
terial life has been generated. I cannot see a flaw in the reasoning ; and it is so simple 
as to render it unlikely that the notion of Bacterial life developed from dead dust can 
ever gain currency among the members of the medical profession. 
It has been said of those whom the evidence adduced in favour of spontaneous genera- 
tion fails to convince, that they seem willing to believe in almost any infringement of 
natural uniformity rather than admit the doctrine*. This surely is an inversion of the 
true order of the facts. Natural uniformity is the record of experience; and, apart 
from the phenomena to be accounted for, there is not a vestige of experience, possessed 
either by the man of science or the human race, which warrants the notion that dead 
dust, and not living seed, is the source of the crops which spring from our infusions 
after their impregnation by the floating particles of the atmosphere. 
* Transactions of the Pathological Society, vol. xxvi. p. 273. 
