55 



all, and the percentage of reduction from previous rates 

 ranges from 49 in Salisbury to 47 in Ely, 43 in Eugby, 

 17 Croydon and Cardiff, to 11 in Merthyr, the lowest of the 13. 



" It will be seen that the reduction of phthisis mortality 

 where certain works have been executed is far too large and 

 far too general to be regarded as an accidental coincidence. 

 And the fact that in some of these cases the diminished 

 fatality of phthisis is by far the largest amendment, if not 

 the only one, which has taken place in the local health be- 

 comes extremely interesting and significant when tlie circum- 

 stances are remembered, that works of sewerage, by which 

 the drying of the soil is effected, must always of necessity 

 precede the accomplishment of other objects (house drainage, 

 abolition of cesspits, etc.) on which the cessation of various 

 other diseases is dependent." 



Dr. Bowditch, working independently and without any 

 knowledge of Dr. Buchanan's experiments, arrived at the 

 same conclusions as regards the mortality in America. 



The remarkable freedom from consumption in some of the 

 drier countries, such as Egypt, Cape of Good Hope, as com- 

 pared with moist Britain, leads one to the same conclusion. 



Dr. Andrews, of Chicago, inquiring into the mortality of con- 

 sumption, came to the conclusion that it is the greatest 

 nearest the sea board, and diminishes as we pass inland. He 

 found that in Massachusetts 25 per cent, of all deaths were 

 due to phthisis; in New York, 20 per cent.; in Kansas, 8 per 

 cent.; in Utah, 6 per cent.; in California, 14 per cent.; but 

 here we are again nearing the Pacific. 



Taken from North to South, the same observer found that 

 in Michigan the death rate was 16 per cent.; in Indiana, 14 

 per cent.; in Tennessee, 12 per cent.; in Alabama, 6 per cent. 

 We may therefore consider that dampness of soil and sea- 

 board towns are favourable predisposing agents of tubercular 

 disease. It would seem as if the bacilli were there in greatest 

 numbers, and most deadly in effects. Localities with dry 

 soils and uniform temperature are least affected. 



2. Pollution of Atmosphere. — Nothing tends to predis- 

 pose to tuberculosis so much as vitiated atmosphere. This is 

 evidenced by the fact that we have consumption most com- 

 mon in large cities ; not only so, but in the parts of them 

 where overcrowding and bad ventilation is at a maximum 

 the mortality is highest. If you compare the death rate in 

 the army now with what it was 50 years ago you will see the 

 effect of good and bad ventilation. From 1830 to 1846 the 

 mean annual mortality from phthisis per 1,000 troops on home 

 service was 7*86. It was greatest in the Foot Guards, 11*9; 

 and lowest in the Household Cavalry, 6*28 ; and the only 



