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innumerable courts, with four and five houses in each, and 

 forming a complete cul de sac. The houses in above half 

 of Leeds, particularly Hunslet, Marsh Lane, &c., are of 

 very inferior description, and many are built upon the 

 potters' clay, out of which the bricks were made to build 

 them. Superior houses, streets, and rooms, induce a 

 greater degree of cleanliness^ and also a better ventilation^ 

 or an easier access of pure air frequently renewed ; a 

 superior well-built house also admits more solar light. 

 The stunted growth of the Samoied, the Ostiaks, the Esqui- 

 maux, the Greenlander, and the Laplander, deprived nearly 

 two-thirds of the year of solar light, indicate its great 

 utility to healthy frames. 



Dr. Laycock, in his Report on the Sanitary State of 

 York, asserts that an elevated situation is of the first 

 importance in that city, and that the variations in altitude 

 from only 13 to 45 feet above the level of the Ouse, 

 gives to different parts of the city a mean age at death 

 of from 22 years to 421 ; and that, even in the labouring 

 class, there is a difference of 12 j years. The greater 

 elevation affords a superior ventilation ; but Dr. Laycock 

 adds, that the effects of deficient drainage are not to be 

 avoided by good ventilation; and, as a proof, names two 

 villages near York, both well ventilated, — that of Rufforth, 

 having a wide stagnant ditch passing through the village, 

 where the mean age at death is 28 years, and that scar- 

 latina there was termed the " black death while the mean 

 age at Acomb is 35i. 



Dr. Emerson, in a paper on the Medical Statistics of 

 Philadelphia, says, " Whilst upon the subject of public 

 hygiene, we cannot restrain ourselves from noticing the 

 subject of ventilation, or a proper supply of pure unrespired 

 air. By far the greatest proportion of the annual sickness 

 and mortality of ordinary seasons is furnished by the narrow 



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