This case came to the attention of the city laboratory, and is of interest in emphasizing the value of laboratory examinations, as well as in pointing out the fallacy of diagnosing oral membranes from their visible character, or by direct microscopic examination alone from throat swabs.
A married woman, with one young child, was seen by her physician on a Tuesday; the symptoms were obscure. Sunday, a whitish, albuminous membrane was observed. She was examined at this time by four physicians, whose opinions were evenly divided as to whether the membrane was that of diphtheria or of Vincent's angina. A swab was submitted to the city laboratory, where direct microscopic examination revealed myriads of spirochetes and fusiform bacilli. An immediate report of Vincent's angina was made. On the following day, however, the cultures showed a very profuse growth, almost in pure culture, of diphtheria bacilli of the slender, granular type.