A DIFFERENTIAL MEDIUM FOR THE MENINGOCOC- CUS AND GONOCOCCUS'

The meningococcus and gonococcus often give rise to lesions in the human being which are of the gravest import. It is, therefore, highly desirable that a differential diagnosis between these two and other gram-negative cocci should be made as early as possible. Workers in hospital laboratories have encountered various difficulties in the practical differentiation of these or-ganisms. The difficulties lie mainly in the slowness of acid production on solid media in general use, and in the frequent failure of the organisms to multiply in fluid media. Numerous attempts have already been made to remedy these difficulties. After a considerable study of the factors influencing the growth and growth products of Neisseria, a medium has been obtained which we believe offers a practical means by which an early differential diagnosis can be made. The medium to be described consists of whole serum from which the fermentable substances and diastase have been re-moved and to which have been added a concentrated broth containing inorganic salts and a carbohydrate and indicator. Differential identification can usually be established in 12 to 24 hours. REVIEW OF LITERATURE Bumm (1885), who first successfully cultivated the gonococ-cus, grew it on solidified human placental blood. Later investi-gators added unheated proteins to agar for the cultivation o