ORGANIC MATTER OF HUMAN BREATH. 



241 



many years, chiefly on the Continent, on the subject of 

 spontaneous generation, and on the causes of fermentation, 

 turns entirely upon the difficulty of keeping out all taint 

 of organic matter from the atmosphere. 



I do not know who first proposed the use of cotton wool 

 as a filter for the air ; but several investigators have cer- 

 tainly used it. Schwann, Schroeder, and Dusch (Annales 

 Ch. Pharm. Ixxxix. 332), Helmholtz (Journal de Chemie, 

 xxxi. 434), Van den Brock (Ann. Ch. Pharm. cxv. 75). 



Pasteur, by using gun-cotton as his filter, and then dis- 

 solving this substance in ether, was able to demonstrate 

 in many ways the presence of numerous germs and spores 

 in the atmosphere. 



It is to Dr. Angus Smith that we owe the discovery of 

 the extreme readiness with which living organisms are 

 formed in the condensed breath of crowded meetings. 



Amongst his other elaborate researches upon the air of 

 towns. Dr. Smith has all along included this now prominent 

 subject, and has frequently called attention to the varying 

 amounts of organic matter in the air of the country and 

 that of towns, especially in the crowded courts and alleys 

 of this city. 



The following Table gives the quantity washed down by 



rain in different places, determined by the Wanklyn and 



Chapman method : — 



Table I. 



Ammonia in Rain-waters. 



Place. 



Ross, near Helensburgh 



Clydeford, Glasgow 



London Hospital 



Glasgow, St. Rollax . 

 Netherfield 



Manchester 



New castle-on -Tyne . , 



Date. 



Jan. 16, 1869. 



Jan. 



1869. 



Feb. 



1869. 



>j 



j> 



;> 



j» 



Dec. 



1868. 



Jan. 



1869. 



Dec. 



1868. 



)> 



n 



Ammonia, parts 



in 1,000,000, 



or grammes in 



a cubic metre. 



O'OO 

 1-25 

 2 

 2"2 



3 



575 



5'5 



6 



5' & o'6 



Ammonia 



of 

 albumen. 



o 



O 



o"3 



0-3 



0-4 



o 



o 



I 



o 



SER. III. VOL. IV. 



R 



