1875.] buy [Blasius. 



Dr. Smith made an experiment witli a bottle holding five litres, which 

 was refilled five hundred times with Manchester air. Dancer in examin- 

 ing this quality of air with magnifying powers from 120 to 1, 600 diameters 

 of an inch found the following bodies : 



1. Particles of vegetable tissue, many of them partially burnt and quite 

 brown in color. 



2. Fragments of vegetation resembling in structure hay, straw and hay 

 seeds. 



3. Hairs of plants and fibres resembling flax. 



4. Cotton fibres both white and colored. 



5. Starch granules. 



6. Wool white and colored. 



7. In greatest abundance fungoid matter, spores and sporidia varying 

 in size from j^^ lyo to 50 Voo of an inch in diameter. 



Many of the spores were living and developed forms resembling rust and 

 mildew. A calculation was made as to their number in the following 

 manner : 



Under each field of the microscope there were more than one hundred 

 spores. In each drop of liquid there were over 250,000 ; the whole quan- 

 tity consisting of one hundred and fifty drops there were in this water no 

 fewer than 37| millions of spores visible. This quantity of air is the 

 amount respired by an average sized man actively employed during 

 ten hours in Manchester. 



There is then hope that science soon will trace the source of many if not 

 all of those mysterious deadly diseases and epidemics, and in finding their 

 source, the remedy and preventive will be furnished at the same time. So 

 much, however, is now already known that those destructive minute or- 

 ganisms in company with the well-known poisonous and noxious gases, 

 originate principally in localities where vegetable and animal matter are 

 decomposing ; in thickly populated cities, on and underneath the pave- 

 ment, gutters, yards, — in swamjjs and rivers into which sewers throw 

 their contents. Here the air must become, so to say, saturated with 

 these deadly poisons. We, therefore, understand that thoughtful people 

 abhor such places, and flee away from them. But as the air loaded with 

 these deadly poisons, does not stay where it generates, nor flow promis- 

 cuously in all directions, it becomesof some importance to know where we 

 have to go, soasnotto meetit; and here comes the youngest of the physical 

 sciences, Meteorology to our assistance. In a lecture which I had the 

 honor of delivering before you some two years ago, I showed that air 

 in its motion follows strict laws the same as water, and that the direc- 

 tion and nature of its currents are dependent upon the season, the configu- 

 ration and nature of the surface of the earth. According to these laws we 

 experience in our latitude during Summer a prevailing current from the 

 southern semi-circle principally from the southwest, south or west ; in the 

 Winter a prevailing current from the northern semi-circle, jDi'lncipally from 

 northw3st and north. Air of the same temperature or currents flowing in 



