Abstract
The average rate of disappearance of bacteria sprayed upon the mucous membrane of the nose has been determined for a series of animals, including guinea pigs, rabbits, dogs and humans. The technic finally used was the following: Broth cultures were diluted 1:200 with saline. A spray delivering 0.15 cc. (±0.01) was used to distribute the bacteria in each nares. A swab touched upon the surface of the respiratory portion of the nose at several places in a uniform manner and streaked well over the surface of an agar plate. This technic was repeated at intervals varying from one minute to one hour. An average of 400 experiments in normal humans, using 42 different subjects is shown in the accompanying graph. The average number of viable bacteria sprayed was 20,000,-000. The swab taken immediately after spraying contained an average of 2,000 bacteria. After 5 minutes the number was reduced to about 50 colonies, 10 minutes about 15 colonies, after 15 minutes about 8 to 10 colonies, after 30 minutes about 5 to 10 colonies. At times none were present after this period. After one hour sometimes 1 or 2 colonies appeared, but ordinarily all of the sprayed bacteria were absent from such agar cultures. The same results were obtained with the other animals used by us. There were 185 animal experiments. If the same bacteria are sprayed in the same number in both sides of the nose, immediate swab only being obtained from one side, and after 5 minutes specimen collected from both nares, the rate of reduction in both sides being the same. This type of experiment has been carried out many times with several different time intervals. The mechanical removal of bacteria by swabbing the mucosa does not play a demonstrable rôle in this reaction.
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