LABORATORY DIAGNOSIS OF DIPHTHERIA.

Johns¹ reviews practically the value of examinations of pseudomembranes of the throat. He notes particularly the sources of error; that the fault of not finding the Klebs-Loeffler bacillus in undoubted cases of diphtheria more often lies with the physician preparing the swab than with the bacteriologist making the examination. Among the causes said to interfere with subsequent examination may be mentioned the almost universal habit of treating the throat with some strong antiseptic before attempting to obtain a culture; if the superficial bacilli are not killed by this, the cotton swab certainly absorbs some of the antiseptic solution and this may cause the death of many of the specific bacilli if present. The tube may have been washed with an antiseptic, and some of this being retained in the tube may interfere seriously with subsequent growth; Johns rightly says that the only safe way of preparing these tubes is sterilization