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the exception of intervals of travel he spent the rest of his 

 life, and here all his most important work was done. With 

 characters combining many-sidedness with great intensity 

 of purpose it is often a mere accident that determines the 

 direction the energies shall take. Such an accident occurred 

 in the career of Dr. Smith. The Health of Towns Com- 

 mission, of which Mr. Edwin Chadwick was the moving 

 spirit, came to Manchester as to other towns to institute 

 inquiries. Dr. Playfair was much interested in these 

 inquiries, and Dr. Smith was engaged in conducting some 

 portion of them, their object being more practical than 

 scientific. This circumstance directed Dr. Smith's attention 

 to sanitary matters, and led him to commence the series of 

 investigations which occupied a great part of his time and 

 attention from the year 1844, up to the time of his death. 



At the time when Dr. Smith commenced his researches 

 sanitary science did not exist, unless a mere collection of 

 unconnected facts can be dignified with the name of science. 

 Since that time much more system has been introduced 

 into the subject, and a great portion of the merit of having 

 developed the purely scientific side of it is due to Dr. 

 Smith. The pathological side of the subject did not, of 

 course, receive as much attention from him as the purely 

 physical; nor did he, we think, at any time pronounce 

 decidedly on the question whether the phenomena with 

 which sanitary science deals are purely organic in their 

 nature or whether they are not also partly due to merely 

 physical causes. What he did was to investigate patiently 

 the physical and chqtnical conditions as regards outward 

 agents, more especially the air we inhale and the water we 

 drink, on which health and disease seem to depend. No 

 doubt, since the time when Dr. Smith entered the field, 

 our views on this subject have altered considerably. It is 

 now held that most diseases, especially those of the zymotic 

 class, are due to the development of organic germs, but the 



