208 
to place a small quantity of pure water in a large bottle, and 
shake it in the air under investigations, repeating the opera- 
tion with renewed volumes of air in the same water ; but 
Mr. Stodder shows how impossible it is to intercept all the 
foreign particles in the atmosphere in this way, inasmuch 
as the smallest bubbles of air which pass through the water 
very much exceed in size the particles of matter which are 
sought for, and myriads must elude observation. A greater 
difficulty, however, is to obtain absolutely pure water for 
such experiments, and whether filtered or distilled water 
was used, a drop evaporated on a glass slide always left a 
deposit of scaly and granular particles. This result, as Mr. 
Stodder justly says, puts an end to this mode of investi- 
gation, and throws a cloud of suspicion on all reported 
researches in this line, when water was the medium used. 
Mr. Bailey stated that the information communicated 
above had been extracted from an official document ema- 
nating from the “ State Board of Health of Massachusetts,” 
and he commended it to the Officers of Health and to the 
Corporations of Manchester and Salford, as an illustration 
of what is required in this neighbourhood. The document 
just issued gives a summary of the work done during the 
past year, and embraces reports upon Public Abattoirs ; the 
Cattle Plague, and its effect on milk; an Outbreak of 
Typhoid Fever; the Overcrowding of Tenements and want 
of Clean Streets in Boston ; Smallpox ; Poisoning by Lead ; 
Trichiniasis in Massachusetts ; Health of the various Towns 
in the State; Homes for the People; Alcoholic Drinks; 
Mortality of the City of Boston ; Ventilation of School- 
houses; Water Supply, and its Comparative Purity; Air, 
and some of its Impurities; Health of Children employed in 
the manufacture of Textile Fabrics; Effect of Sewing- 
Machines on Health, &c. ; and all this at a cost of under 
£600 the year. 
