88 



BACTERIA IN THE AIR 



times more bacteria than the air of a typical above-ground bake- 

 house.* 



Dr Scott Tebb has also made a somewhat parallel examination 

 of the air of London streets as compared with the railway tube of 

 the City and South London railway.f As the result of a large 

 number of investigations carried out in a similar way to the writer's 

 examinations in bakehouses, the following figures were arrived at : 



(iii.) Thirdly, some of the results of the investigations of Graham 

 Smith into the condition of the atmosphere of the House of Commons 

 may be mentioned.^ He used a modification of Frankland's method of 

 filtering the air to be examined (4'5 litres in each case) through glass 

 wool. An air-pump and a rubber tube of 10 feet in length were 

 used for drawing the air through, and gelatine was used as the 

 medium, the cultures being incubated at 20 C. for five days or 

 longer. The results may be expressed in tabular form in three 

 series : 



Similar experiments were performed in the House itself during a 



* Report on Bakehouses in Finsbury (Newman), 1902, p. 51. 



t Report of Public Analyst of Southwark on Condition of Air on City and South 

 London Railway, 1903. W. Scott Tebb, M.D. 

 J Jour. o/Hyg., 1903, pp. 498-513. 



