136 



The ratios of the velocities at Eccles to those at South- 

 port are therefore greatest with south-west and north-east 

 winds, and least with north-west and south-east winds. 

 The great excess of velocity of north-west winds at South- 

 port is very remarkable. 



The results of the above comparison bring out very pro- 

 minently one of the causes of the great salubrity of South- 

 port as compared with the neighbourhood of Manchester, 

 namely, the much greater mean velocity of the wind, in 

 consequence of which the products of decomposition, and 

 and offensive matters generally which are injurious to 

 health, are much more rapidly removed at Southport than 

 at Manchester. 



MICROSCOPICAL AND NATURAL HISTORY SECTION. 

 February 5th, 1872. 



Joseph Baxendell, F.KA.S., President of the Section, in 



the Chair. 



Mr. Joseph Sidebotham, F.R.A.S., called the attention of 

 members to the mass of correspondence in the papers on the 

 origin and spread of Typhoid fever, in which it seems to be 

 considered as proved that the fever is produced by what are 

 termed sewer gases, and the germ theory is entirely ignored, 

 when in all probability it is the true one. The various 

 gases found in sewers are well known, and if produced 

 artificially, as they are in various chemical processes either 

 alone or mixed, are comparatively harmless, even in a more 

 concentrated form than they are ever met with in sewers, 

 at any rate they never produce typhoid fever. If the germ 

 theory be correct the real agents in the spread of this and 

 other similar diseases are germs or particles, many of them 

 sufficiently large to be detected by the miscroscope ; these 

 are met with in sewers, but probably not generated there, and 



