234 



Cincinnati Society of Natural History. 



Table II. 



From the above it is seen that in all, seventeen experiments 

 were made, with a total of twenty-five determinations. These 

 extend from October to April, a period of seven months. The 

 determinations were made partly at the University and partly 

 at the residence portion of Albuquerque (S. Arno St.) Those 

 made at the former place were made for the most part by the 

 flask method, and as the results are somewhat doubtful, they 

 will be eliminated from the following discussion. This leaves 

 only experiments 39,40, 48, and 49 (five determinations) made 

 at the University. These five give an average of only 41.6 

 bacteria per cubic meter of air. Taking the eleven determina- 

 tions made by the same method in the residence district of 

 Albuquerque, we have an average of 143 bacteria per cubic 

 meter, or more than three times the number found in the 

 mesa air. It is recognized that these figures are very imper- 

 fect, due to the limited number of experiments made, but 

 they may serve, in a measure, to indicate the conditions as 

 compared with other places. If we take for comparison 

 Miquel's table p. 213, we find that for autumn, winter, and 

 spring we have an average of 6,016 bacteria per cubic meter 

 for Paris and 220" for Mont-Souris. That is, the air of the 

 residence portion of Albuquerque contains rather more than 

 half the number found in Mont-Souris park, while the mesa 

 air contains less than a fifth of that number. 



While the number of bacteria per volume are undoubtedly 

 less in our arid district than for similar places in more humid 

 climates, the number found is still quite large; larger, in fact, 

 than had been expected. The explanation of this fact is 

 found in the greater facilities afforded by our climate in trans- 

 porting into the air such organisms as may be able to thrive. 

 The pulverization of the ground and the creation of dust that 

 is readily carried into the air by our relatively high winds, 

 undoubtedly accounts largely for the condition. In other 

 words, while as many bacteria may not exist in a dry climate 

 as in a moist one, the opportunities for carrying them into 

 the air are relatively much greater, and consequently we find 

 the atmosphere, not free, but well laden with bacterial life. 



And here, perhaps, a practical application may be made to 

 the conditions found in our locality. While the intense sun- 



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