296 PATHOGENIC BACTERIA. etc. Whoever comes in contact with such materials is in danger of infection. It is of great interest to notice the remarkable results obtained by Biggs, Park, and Beebe in New York, where the bacteriological examinations conducted in connection with diphtheria show that the virulent bacilli may be found in the throats of convalescents as long as five weeks after the discharge of the membrane and the commence- ment of recovery, and that they exist not only in the throats of the patients themselves, but also in the throats of their care-takers, who, while not themselves infected, may be the means of conveying the disease from the sick-room to the outer world. Even more extraordinary are the observations of Hewlett and Nolen,1 who found the bacilli in the throats of patients seven, nine, and in one case twenty-three weeks after convalescence. The importance of this observation must be apparent to all readers, and serves as further evidence why most thor- ough isolation should be practised in connection with this dreadful disease. Park2 found virulent diphtheria bacilli in about i per cent of the healthy throats examined in New York City. Diphtheria was, however, prevalent in the city at the time. Most of the persons in whose throats they existed had been in direct contact with cases of diphtheria. Very many of those whose throats contained the virulent bacilli did not develop diphtheria. He concludes that the mem- bers of a household in which a case of diphtheria exists should be regarded as sources of danger, unless cultures from their throats show the absence of diphtheria bacilli. In connection with the contagiousness of diphtheria the recent experiments of Reyes are interesting. He has demonstrated that in absolutely dried air distributed diphtheria bacilli die in a few hours. Under ordinary 1 Brit. Med. Jour., Feb. i, 1896. 2 Report on Bacteriological Investigations and Diagnosis of Diphtheria, from May 4, 1893, to May 4, 1894, Scientific Bulletin No. /, Health Depart- ment, City of New York.