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stances, and sporangia of fungi and monads in considerable 
quantity .” Mr. Dancer’s * researches on the air of Manchester 
are also of great interest, more especially as he gives an esti- 
mate of the amount of spores present in the specimens of air 
examined. He says that there were m 2,495 litres of the at- 
mosphere (an amount that would be breathed by any ordinary 
individual in about ten hours) no less than 37,500,000 spores, 
exclusive of other materials . And besides those whose re- 
searches we have mentioned, there are many others whose 
inquiries all point in the same direction. 
But it must be confessed that the opposite side is, in regard 
to the absence of spores originating epidemic diseases, not 
devoid of evidence also. It can name no less authorities than 
Ehrenberg, the greatest infusorial investigator in the world ; 
Pouchet, the celebrated supporter of the well-known doctrine 
of spontaneous generation ; the Boyal College of Physicians ; 
and MM. Joly and Musset ; besides various other less celebrated 
authorities. But the first can only be cited as opposed to the 
idea that there are the germs of infectious diseases in the 
atmosphere ; for he shows most conclusively, by infinitely the 
most extensive of researches, that the air contains an amount 
of animal life that is something extraordinary. But, says Dr. 
Cunningham,! when speaking on this part of the subject, “no 
special forms of infusoria or spores were to be found in the 
atmospheric dust during the epidemic of cholera in 1848.” So 
we may almost count Ehrenberg on the other side, i.e. among 
the anti- con tagionists. In point of fact the only men of great 
reputation upon this side are MM. Pouchet, Joly, and Musset. 
Their researches are really most remarkable, for they seem to 
have observed none whatever of the hosts seen by numerous other 
workers. Of course they did find (more especially Pouchet) 
some corpuscles and a few other organisms, but nothing at all 
to account for the multitude that were developed in water ex- 
posed to the air. 
Now we must remember that these three (Pouchet, Joly, 
and Musset) were the special advocates of spontaneous genera- 
tion, and that therefore they could not be expected to find an 
ample supply of animal and vegetable life already existing in 
the atmosphere. But it may be said we have no right to 
accuse them of falsity, and therefore we declare that we do 
not do so ; but what we do say is, that persons who were 
engaged in a desperate argument against the existence of these 
germs in the atmosphere, were not the most likely persons to 
find them in that position. 
* They were published in the “Proceedings of the Literary and Philoso- 
phical Society of Manchester.” 
+ “ Microscopic Examinations of Air,” 1874. 
