270 MR. J. B. DANCER ON THE SOLID PARTICLES 



life; Mr. Dancer says, ^^few living organisms were no- 

 ticed." However, I defer to him in all matters con- 

 nected with the microscope. There were many forms 

 evidently organic, although not in motion. My belief 

 was that they might be developed by care, as I had 

 treated others similarly many years ago. In a memoir 

 ^^ On the Air and Water of Towns '' (Report of the 

 British Association, 1848), speaking of matter from the 

 breath, I said, ^' If it be allowed to stand for a few days 

 (about a week is enough), it will then show itself more 

 decidedly by becoming the abode of small animals," &c. ; 

 and when speaking of the condensed matter on glass and 

 walls, it was said, "If allowed to stand some time, it 

 forms a thick apparently glutinous mass ; but when this 

 is examined by a microscope, it is seen to be a closely 

 matted confervoid growth, or, in other words, the organic 

 matter is converted into confervse, as it probably would 

 have been into any kind of vegetation that happened 

 to take root." I was quite familiar, therefore, with the 

 idea of developing these germs ; the matter is found in the 

 exhalations, and on that they may feed. It seems as if a 

 choleric germ or a plague germ might grow there indiffer- 

 ently ; and I do not see any thing more mysterious than 

 natural action, which^ however, is wonderful enough. 



XXI. Microscopical Examination of the Solid Particles 

 collected by Dr. Angus Smith from the Air of Manchester. 

 By J. B. Dancer, F.R.A.S. 



Eead March 3i8t, 1868. 



The air had been washed in distilled water, and the solid 

 matter which subsided was collected in a small stoppered 



