48 STUDY AND IDENTIFICATION OF BACTERIA. 



likewise grows on ordinary blood-serum. The M. catarrhalis will 

 grow on plain agar as well as on the other media. 



Gonococcus (Neisser, 1879). This organism is characteristically 

 a diplococcus, the separate cocci being plano-convex with their plane 

 surfaces apposed. (Biscuit shape, coffee-bean shape.) They are 

 generally found grouped in masses of several pairs, most strikingly in 

 pus cells or epithelial cells, but also found extracellularly. Except in the 

 height of the disease, there is a great tendency for the organisms to show 

 involution forms, so that instead of biscuit-shaped diplococci we have 



FIG. 14. Gonococcus. Film from urethral pus. (Coplin.) 



round, irregular and uneven cocci. It is therefore advisable in search- 

 ing smears from chronic gonorrhoea to continue the search of Gram 

 stained specimens until some fairly typical diplococci are found. 

 There is nothing requiring greater discrimination than a diagnosis 

 from such a smear. At the commencement of a gonorrhcea the 

 epithelial cells are abundant and gonococci are found adhering to them 

 or lying free. Later on, at the acme of the discharge (the creamy, 

 abundant discharge), it is in the pus cells we find them and they may be 

 so abundant that 10 to 20% of the pus cells may contain them. In 



