380 COCCI PATHOGENIC FOR DOMESTIC ANIMALS AND MAN 



gelatin plates at the end of twenty-four hours shows small, white, 

 circular colonies, which increase rapidly in size. The colonies on 

 agar are grayish white and moist. On blood serum slants an abundant 

 grayish-white, moist, and shiny growth is formed, and on potatoes a 

 thick, yellowish- white shining layer. Milk is not coagulated. Lactose 

 and glucose are fermented with the formation of acid. The diplo- 

 bacillus of pneumonia has not been encountered as the natural cause 

 of disease in domestic animals. 



GONOCOCCUS. 



The gonococcus, or Micrococcus gonorrhoeae, is an organism 

 occurring in pairs and occasionally in tetrads. The individual cocci 

 forming the pair are flattened at their opposing surfaces, often some- 

 what resembling a kidney or coffee bean in form. The organism is the 

 cause of gonorrheal inflammation of the urethra in men and women. 

 It also penetrates deeper into the genito-urinary tract, and causes 

 epididymitis, ovarian abscess, salpingitis, inflammation of the pelves 

 of the kidneys (pyelonephritis), peritonitis, inflammation of the 

 joints, and endocarditis. It is generally spread in sexual intercourse. 

 It may also be transferred with the fingers or otherwise to the 

 eye and cause a very dangerous conjunctivitis. The organism in 

 pus is frequently found intracellularly in the protoplasm of the 

 leukocytes. It stains very rapidly with the watery anilin stains, but 

 also loses the stains very easily, and is Gram negative. It is difficult 

 to grow on artificial culture media. The best medium is an ordinary 

 agar, two parts, to which one part of sterile human-blood serum 1 has 

 been added. The ingredients are mixed after the melting of the agar 

 and again solidified after inoculation from fresh gonorrheal pus. 

 Gonococci form colonies on such serum agar after sixteen to twenty- 

 hours, but they are so small as to be only visible with a good hand 

 magnifying glass or the low power of the microscope. After twenty- 

 four hours the colonies have attained the size of a pinhead and do not 

 grow much larger. They are light gray, translucent, and of a peculiar 

 tenacious, slimy consistency. They generally remain round, well 

 defined, and do not, as a rule, become confluent, but may touch each 

 other. The culture soil in transmitted light somewhat resembles the 

 surface of ice which has been much cracked. In exceptional cases the 

 colonies become confluent and form grayish-white films. Colonies 

 of gonococci closely resemble colonies of the Diplococcus lanceolatus, 

 but the former are generally somewhat larger, less translucent, and 

 more highly colored. Gonorrhea is a strictly human disease. It does 

 not occur naturally among animals, and even artificial inoculation is 

 very difficult and rarely successful. Mice in intraperitoneal infection 

 develop a localized peritonitis. 



1 Ascitic, hydrocele, or pleuritic fluid may be used in place of the human-blood serum in 

 the preparation of the medium. 



