Show MICROORGAXISMS IY TIlE AIR 11 To the unassisted eye the presence of even any solid particles in the air is as a rule entirely invisible We say this is so I as a rule for there are crcumstanr when the solid particles in the air are rendered visible Every ono is aware of the appearance of a stream of sunlight introduced through a slit or hole in the shutter of a darkened room Under such circumstances the air through which the sunlight passes is seen to be full of in nute dust particles yet the gay motes which are thus seen to p < > oolt the sunbeam sun-beam constitute after a only a very insignificant fraction of tht total numbr the air contains for thousanas of them I are far too minute to bE visible to thf I naked eye Among these latter are the germs i It is only indeed with the aid of our most powerful microscopes that we are enabled to discern these latter and form any estimate of their size Many of th mare m-are less than the one twentythousandth of an inch In the words of Prof Pery F Frankland one of our first experts on this subject four hundred millions of these organisms could be spread over one square inch in a single layer Thus we could have a population one hundred times as great as that of London settled on an area of a single square inch without with-out giving to each individual organism not three acres which certain politicians tell us are necessary for the individual man but one four hundredthmillionth ota ot-a square Inch which is quite adequate fora citizen in the commonwealth of microorganisms mi-croorganisms The Gentlemans aiaga sine I |