ORGANIC IMPURITIES IN AIR. 241 



new atmosphere. Persons from the Highlands 

 of Scotland frequently experience this on enter- 

 ing Glasgow, the air of which impresses the 

 same feeling as that of a forge or glass-house ; 

 occasionally they are unable to bear its exces- 

 sive impurities. It has been found that such 

 matters are never absent from the air, and that> 

 let it rain ever so much, or long, in a large 

 city, with every shower a quantity of organic 

 ingredients will be brought down. This mat- 

 ter is capable of promoting animalcular life to 

 some extent, and small specimens may be seen 

 moving solitarily in it. If allowed to stand in a 

 bottle this may be more clearly detected. Vogel 

 and Dr. Southwood Smith have both found 

 organic matters present in the atmosphere. 



Difficult, and intricate as the whole question 

 is, this general fact appears to flow out of the 

 preceding remarks that whatever be the ex- 

 traordinary causes of epidemics and plagues of 

 an aerial kind, the sources of the commoner 

 disorders belonging to this class are discoverable 

 in the putrefying filth which the negligence of 

 our poorer fellow-countrymen suffers to accu- 

 mulate in death-productive heaps on the walls of 

 and round about their dwellings. Nothing, in 

 fact, can be more confidently affirmed than that 

 filth and fever stand in the relation of cause and 

 effect ; and that poverty, although the first, is 



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