When, a year ago, the writer, in a paper on Theater Sanitation' presented at the annual meeting of the American Public Health Association, stated that "chemical analyses show the air in the dress circle and gallery of many a theater to be in the evening more foul than the air of street sewers," the statement was received by some of his critics with incredulity. Yet the fact is true of many theaters. Taking the amount of carbonic acid in the air as an indication of its contamination, and assuming that the organic vapors are in proportion to the amount of carbonic acid (not including the CO2 due to the products of illumination), we know that normal outdoor air contains from 0.03 to 0.04 parts of CO2 per 100 parts of air, while a few chemical analyses of the air in English theaters, quoted below, suffice to prove how large the contamination sometimes is:
| Strand Theater, 10 p. m., gallery | 0. 101 | parts CO2 per 100. |
| Surrey Theater, 10 p. m., boxes | 0.111 | """ |
| Surrey Theater, 12 p. m., boxes | 0.218 | """ |
| Olympia Theater, 11.30 p. m., boxes | 0.082 | """ |
| Olympia Theater, 11.55 p. m., boxes | 0.101 | """ |
| Victoria Theater, 10 p. m., boxes | 0.126 | """ |
| Haymarket Theater, 11.30 p. m., dress circle | 0.076 | """ |
| City of London Theater, 11.15 p. m., pit | 0.252 | """ |
| Standard Theater, 11 p. m., pit | 0.320 | """ |
| Theater Royal, Manchester, pit | 0.2734 | """ |
| Grand Theater, Leeds, pit | 0.150 | """ |
| Grand Theater, Leeds, upper circle | 0.143 | """ |
| Grand Theater, balcony | 0.142 | """ |
| Prince's Theater, Manchester | 0.11-0.17 | """ |
Analyses made by Drs. Smith, Bernays, and De Chaumont.
Compare with these figures some analyses of the air of sewers. Dr. Russell, of Glasgow, found the air of a well-ventilated and flushed sewer to contain 0.051 vols, of CO2. The late Prof. W. Ripley Nichols conducted many careful experiments on the amount of carbonic acid in the Boston sewers, and found the following averages, viz., 0.087, 0.082, 0.115, 0.107, 0,08, or much less than the above analyses of theater air showed. He states: "It appears from these examinations that the air even in a tide-locked sewer does not differ from the standard as much as many no doubt suppose."
A comparison of the number of bacteria found in a cubic foot of air inside of a theater and in the street air would form a more convincing statement, but I have been unable to find published records of any such bacteriological tests. Nevertheless, we know that while the atmosphere contains some bacteria, the indoor air of crowded assembly halls, laden with floating dust, is particularly
