242 DR. ARTHUR RANSOME ON THE 



In an Appendix to Dr. Angus Smith's last report to the 

 Privy Council upon the working of the alkali Acts^ Mr. 

 Dancer has remarked upon the nature of the organic matter 

 contained in the washings of 2495 litres of the air of 

 Manchester. He discovered in them many forms of life, 

 fungoid matter, sporidia and zoospores, and much lifeless 

 organic substance, vegetable tissue, partially charred objects, 

 fragments of weather-worn vegetation, hairs of leaves, fibres, 

 cotton filaments, granules of starch, and hairs of animals. 



Mr. Dancer makes the calculation that about "^ 2>l2 

 millions " of spores or germs of organic matter would be 

 contained in the quantity of air examined, an amount 

 "which would be respired in about 10 hours by a man of 

 ordinary size when actively em ployed. '^ 



I would submit, however, with deference to Mr. Dancer, 

 that in this calculation there is a serious possibility of 

 error. There seems to have been a considerable interval 

 of time (how long, is not stated in Dr. Smith's Report) 

 between the commencement of the collection of the fluid 

 and the examination of it by the microscope. It is well 

 known how rapidly organisms increase in numbers in 

 suitable fluids ; aiid it seems reasonable to believe that 

 many of the spores discovered by Mr. Dancer may have 

 been developed in the fluid itself. 



I have myself made a few observations upon the organic 

 contents of respired air, which may be interesting at the 

 present time. 



Several years ago a letter, by a person who signed himself 

 "Investigator," appeared in the ^ Times' newspaper, urging 

 the microscopic examination of the air during the preva- 

 lence of epidemics, blights, and murrains. Shortly after 

 this, in the year 1857, I adopted his method, and exposed 

 glass plates, covered with glycerine, in diff*erent places — 

 amongst others, in the dome of the Borough Gaol in Man- 

 chester. All the respired air from the cells in this build- 

 ing is conducted into the dome by the system of ventilation 



