94 Dr. R. A. Smith, an the Organic Matter of the Air. [March 25, 



At an early opportunity all the experiments made will be published ; 

 but we may already see the range of the action of this test to be so 

 great as to make it promise to be of some practical as well as scientific 

 value. Dr. Southwood Smith has observed that the facts on which 

 sanitary economy are built are exceedingly difficult of comprehension 

 by a large number of people, because the cause of the evil cannot be 

 brought directly under the observation ; if however any plan were 

 invented of showing that these dreaded emanations existed even when 

 the senses could not perceive them, belief would be easily gained, and 

 the requisite carefulness would then take place. If the method ex- 

 plained be found to be no more valuable than this, it will at least not 

 be reckoned among useless discoveries. 



We may hope, however, that it will be found to prove not only that 

 much of that which we have already known is true, but that many 

 other now hidden things are true also ; we may find that every wind 

 will have attached to it its mark of unwholesomeness with respect to 

 this test, and that every season also will have its co-efficient. It may 

 also be found that changes of season or of condition of the air will be 

 ascertained with much more certainty, delicacy, and rapidity than now. 

 We may even hope to find some premonitory symptoms of disease in 

 the atmosphere before it affects the human body ; the exciting cause 

 itself existing long before it has been able to take effect, so that useful 

 precautions may be made in time, and an efficient defence prepared. 

 At the same time no proof whatever has yet been given that a plague 

 or any infectious disease can be estimated by it, although reason has 

 been given for such an expectation, whilst the air over different fields 

 differs enough to promise some knowledge of miasm. 



But what is abundantly established and made clear to the eye is 

 that the air of our large cities is sufficiently impure to account for 

 much of their unhealthiness, and the air of our hills and seas and lakes 

 sufficiently pure to account for its salubrity. It is to be hoped that 

 greater consequences will follow in proper time ; although this itself was 

 needed to set at rest some questions which have cooled the enthusiasm 

 of many in the cause of sanitary reform. 



[R. A. S.] 



