COMPARATIVE MERITS OF PAVEMENTS. 9 
and poisonous to the organs of respiration. Its damage to furniture, though se- 
rious, is unimportant in this connection. In the side gutters and underlying soil 
the foul matter exists in a more concentrated form, the supply being constantly 
renewed from the crown of the street, and in many districts, from the filthy sur- 
face drainage of backways and alleys peopled by the poorer classes. Is it too 
much to say that under such circumstances the infant population, and especially 
the children of poor people, in large towns, can only be reared under such pre- 
dispositions to disease as will constitutionally render them an easy prey to epi- 
demics in maturer years? . 
The foregoing are some of the leading hygienic objections to pavements laid 
in blocks, whether of stone, wood or other material. There are others peculiar 
to wood alone, arising from its decay, its natural porosity, and the spongy charac- 
ter conferred upon it by wear and crushing. 
‘‘Impregnation of wood with mineral matters, to preserve it from deen, 
may diminish these evils, but nothing as yet tried prevents the fibers being sepa- 
rated, and the absorption of dung and putrescent matter by the wood being con- 
tinted. The condition of absorbing mere moisture is of itself bad, but when the 
surface absorbs and retains putrescent matters it is highly noxious. The blocks 
of pavement with this material are separated by concussion, and are thus render- 
ed permeable to the surface moisture. Mr. Sharp, who examined some blocks 
taken up for re-pavement, states that he found them perfectly stained and satu- 
rated with wet and urine at the lower portions, while the upper portions were dry. 
Mr. Elliott, a member of the society, and for many years a deputy of the Com- 
mon Council of the city of London, has carefully observed the trials of new modes 
of pavement there, and objects to wood that it is continuously wet and damp. 
Wood is wet or damp, more or less, except during continued very dry weather. 
Its structure is admirably adapted to receive and hold, and then give off in evap- 
oration, very foul matters, which taint the atmosphere and so far injure health.” 
(Report of P. Le Neve Foster, Secretary Society for the Encouragement of Arts, 
Manufactures and Commerce: London, 1873. 
Prof. Fonssagrives, of France, says: ‘“‘The hygienist cannot, moreover, 
look favorably upon a street covering consisting of a porous substance capable of 
absorbing organic matter, and by its own decomposition giving rise to noxious 
miasma, which, proceeding from so large a surface, cannot be regarded as insig- 
nificant. Jam convinced that a city with a damp climate, paved entirely with 
wood, would become a city of marsh fevers.” 
The dust produced by the abrasion and wear of a wooden pavement is re- 
garded by physicians as extremely irritating to the organs of respiration and to 
the eyes, and being light in weight it floats longer in the atmosphere and is car- 
ried to a greater distance, than that from any other suitable material in use for 
street pavements. 
The evidence from a sanitarian point of view, against the use of wood for 
_ paving purposes in populous towns, is very strong, but the evils are not developed 
to the same extent in all localities. Decomposition begins in two or three years 
