1873O Atmospheric Life Germs. 225 



a tube containining a plug not of cotton-wool, as in the experi- 

 ments of Schroeder, but of soluble pyroxyline, such as is used 

 for making collodion. The amount of air aspirated in a 

 given time was accurately measured, and after a sufficient 

 interval the soluble cotton plug was removed and treated with 

 its solvents, alcohol and ether. After allowing the dust to 

 subside in a tube, the collodion was syphoned off, and more 

 alcohol and ether added to effect the perfect removal of the 

 collodion. The completely-washed dust was placed on a 

 microscope slip and examined in a drop of water. By 

 ordinary methods the action of different reagents, such as 

 iodine water, potash, sulphuric acid, and colouring matters 

 on the particles was tried. This process disclosed the fact 

 that there is in ordinary air a variable number of corpuscles, 

 ranging in size from extreme minuteness up to the diameters 

 of o*oi m.m. to 0*015 m.m. ; some translucent particles of 

 a regular shape so closely resemble the spores of the most 

 common fungi that the most able microscopist could see no 

 difference in them. The corpuscles were evidently organised, 

 resembling completely the germs of the lowest organisms, 

 and so diverse in size and structure as to belong without 

 doubt to very various species. The soluble cotton used was 

 previously tested and found to contain no residue insoluble 

 in alcohol and ether beyond a fibre or two. By exposing a 

 plug of pyroxyline for twenty-four hours to a current of air 

 passing at the rate of a litre the minute after a succession 

 of fine spring days, it was found that many myriads of 

 organised corpuscles were collected. 



Experiments with Heated Air. 



Although it appears there are in air organised corpuscles 

 in great numbers which are indistinguishable from the 

 germs of the lowest organisms, is it really a fact that 

 amongst these there are particles capable of germination ? 

 This interesting question was answered in a conclusive 

 manner. Firstly, the facts announced by Schwann were 

 firmly established, although they had previously been 

 attacked by Mantegazza, Joly and Musset, and Pouchet. 

 The solution, sealed up in flasks, was one extremely liable 

 to change ; its composition was — 



Water 100 parts. 



Sugar 10 ,, 



Albumenoid and mineral matters) 



r , ho'2 to o*7 parts, 



from yeast j ' v 



Boiled for two or three minutes, and then placed in contact 

 VOL. III. (n.s.) 2 G 



