. Preventive medicine and hygiene. is made byplacing the thumb over the cotton stopper and apply-ing the aspirator; if the suction is Aveak or absent thecorks must be tightened or the tubes discarded. Allcorks should be tightened and connections wired andthe apparatus sterilized before using the filters. Thecollection of the sample should take from 1 to 3 min-utes per liter. After filtering a definite volume through the tubesthe sand is poured into 10 c. c. of sterile water, thor-oughly shaken, and aliquot portions plated in ordinarynutrient agar, all plates being made in duplicate. Theplates
. Preventive medicine and hygiene. is made byplacing the thumb over the cotton stopper and apply-ing the aspirator; if the suction is Aveak or absent thecorks must be tightened or the tubes discarded. Allcorks should be tightened and connections wired andthe apparatus sterilized before using the filters. Thecollection of the sample should take from 1 to 3 min-utes per liter. After filtering a definite volume through the tubesthe sand is poured into 10 c. c. of sterile water, thor-oughly shaken, and aliquot portions plated in ordinarynutrient agar, all plates being made in duplicate. Theplates are incubated at room temperature for five days,when final counts are made. Eettgers Method.—A new and improved methodof enumerating air bacteria has just been described byEettger,^ which commends itself as the best method yet devised. Themethod consists of bubbling a given quantity of air through salt solu-tion. The bacteria in the air are trapped in the salt solution, which^Jour. of Med. Res., June, 1910, XXII, 3, pp. Fig. 91.—DoubleAspirator. BACTERIA IX THE AIE 719 may then be planted in tlie usual way and the number of coloniescounted. Air and Infection.—The air was long regarded as the vehicle andeven the source of the communicable diseases. Theories, such as nox-ious effluvia, poisonous emanations, and infectious miasmata, gave waywith the advent of bacteriology. When the early classical researchesof Pasteur, Tyndall, and others showed that bacteria exist in the airalmost everywhere in greater or in lesser numbers, the conclusion wasjumped at that the air must be particularly dangerous. Within recentyears, however, we have learned that the air is not very much to befeared on account of the bacteria it may carry, except under certainoccasional circumstances. This change in our views during recent timesis nowhere better illustrated than in the relation of the air to the early days of antiseptic surgery so much fear was enter-tained for the ba
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Keywords: ., bookauthorwh, bookcentury1900, bookdecade1910, booksubjecthygiene
