PATHOGENIC BACTERIA. 167 



VIII. Diplococcus Pneumoniae. 



This is found in normal saliva and in the sputum of croupous 

 pneumonia. The cells are lance-shaped, occurring in pairs, sur- 

 rounded by a capsule. It is a non-motile facultative saprophyte, and 

 produces round, grayish- white colonies on nutrient gelatin, and is 

 non-liquefying. It may be stained by Gram's method or with the 

 aqueous solutions of aniline dyes. Injected into a mouse, it pro- 

 duces spetic93mia. 



IX. Bacillus Coli Commune. 



The colon bacillus is found associated with typhosus in typhoid 

 fever, and with Micrococcus urcw in cystitis. It is recognized as 

 the cause of most of the summer complaints among children, and is 

 almost invariably found in the feces of healthy persons. It is mo- 

 tile, grows luxuriantly on ordinary media; produces acids, gases, 

 and indol; coagulates milk, and does not react with typhoid blood. 

 It may be stained with fuchsin or gentian- violet. 



X. Micrococcus Gonorrhoeae, 



This microbe is the cause of gonorrhoea. It occurs in gonorrhceal 

 discharges from the urethra, the somewhat hemispherical cells oc- 

 curring on the surfaces of epithelial cells, or in pus-cells in pairs 

 or tetrads. It is a non-motile facultative anaerobe. The cocci do 

 not stain by Gram's method, but may be stained with Loffler's 

 methylene blue or aqueous solutions of fuchsin and gentian-violet. 

 It does not grow upon gelatin. 



Other species which may be studied are the Bacillus tetani of 

 tetanus, Bacillus influenza of influenza, Baccillus leprce of leprosy, 

 Bacillus mallei of glanders, Spirillum cholerce of cholera. 



Laboratory exercise No. 58. StapJiylococcus pyogenes aureus. Make a 

 systematic study of this species and write out a full outline according* 

 to the form given on page 155. Stain by method No. 10. and study with 

 one-twelfth oil-immersion objective. Make out single cells and a zo- 

 oglcea. 



Laboratory exercise No. 59. Streptococcus pyogenes. Make a sys- 

 tematic study of this species, preparing an outline and making the 

 required drawings. Stain with aqueous or carbol fuchsin. Observe 

 single cells and slender bead-like filaments. 



