ORGANISMS WHICH PRODUCE DISEASE 61 



6. The Gram-negative Group of Cocci. The various cocci 

 (Staphylo-, Strepto-, and Pneumo-cocci and M. tetragenus) 

 mentioned above are all stained positively by a special 

 differential stain known as Gram's method. There are also 

 several very important cocci which do not stain by this 

 method, and which are therefore known as the Gram-negative 

 group. Of these the Gonococcus, the Meningococcus, and Micro- 

 coccus catarrhalis are the most important. 



The Gonococcus, also known as the Micrococcus gonor- 

 rhoeae, is the cause, not only of the all too common venereal 

 infection of both sexes from which it derives its name, but 

 it may produce widespread and very intractable secondary 

 infections of the bladder, uterus and its appendices, peri- 

 toneum, joints (" gonorrhoeal rheumatism"), and even ulcera- 

 tive endocarditis or heart disease. It is found in the purulent 

 discharge from gonorrhoea or gleet, and in gonorrhoeal con- 

 junctivitis or inflammation of the surface of the eye and 

 eyelids. The last-mentioned condition is unfortunately very 

 common in newly-born infants who have been infected at birth 

 from the passages of the mother, but it may also be found in 

 children and older persons from the use of contaminated towels. 

 Many of the cases of partial or complete blindness in our 

 blind asylums are due to its ravages. Animals other than 

 man are practically immune to its action. 



Microscopically, it is found in the discharges sometimes 

 free, but most commonly intracellularly, i.e. within the phago- 

 cytic leucocytes and other cells (see Frontispiece, fig. 23). It 

 is generally found in pairs, each coccus usually somewhat 

 kidney-shaped, with the concavities towards each other. It 

 stains readily with the basic aniline dyes, and, as above men- 

 tioned, it is Gram-negative. 



It is a somewhat difficult organism to grow artificially.' It 

 requires special media blood-serum, or better still, phosphate- 

 agar smeared with blood, kept at body-temperature. It dies 

 off rapidly. 



The Meningococcus or Micrococcus intracellularis men- 

 ingitidis, is the cause of the deadly disease known as epidemic 

 cerebro-spinal meningitis. Isolated or sporadic cases of this 

 disease, which specially attacks children, are not uncommon, 

 but as the name implies, it may occur in epidemic*, and it 

 sometimes even becomes pandemic, i.e. occurring in any country 

 of the world. A few years ago such a pandemic occurred, 

 causing many deaths in Europe, America and elsewhere, as 

 many as eighty per cent, of the cases ending fatally. It is 

 sometimes extraordinarily rapid in its action, death resulting 

 in a few hours ; but usually the disease lasts several days. 



