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THE MICROSCOPE. 



the outset to the counting of these organisms, and to estimating the 

 number that existed in each cubic meter of air, and thus succeeded 

 in determining what influence the seasons, temperature, dryness and 

 moisture had upon their development. The results are as follows: 

 The number of spores belonging to moulds is small in January and 

 February, very small in March, increases in April and May, reaches 



its maximum in June, and finds its minimum in December. The 

 number of such spores per cubic meter of air was found to be, on an 



average: 



January 7,ooo 



February 7.ooo 



May 12,000 



June ^ • 35.000 



