8o 



STUDY AND IDENTIFICATION OF BACTERIA. 



slant smeared with human blood (pigeon's blood is also satisfactory), 

 and then without sterilizing the loop, innoculate a second blood slant; 

 then a third, and possibly a fourth. The colonies appear as very 

 minute dew drop-like points which seem to run into each other in a 

 wave-like way. Lord distinguishes them from pneumococcus colonies 

 by their disappearing from view as you shift from reflected light to 

 direct transmitted light. To test such colonies we should transfer a 

 single colony to plain agar and blood-serum, trying not to carry over 

 any blood. If the least trace of blood is carried over, they may grow 

 on agar or blood serum. Organisms resembling the influenza bacillus 



FIG. 29. The Koch- Weeks Bacillus. (Hansett and Sweet.) 



have been isolated from whooping-cough. Such organisms have 

 also been found in the fauces of well persons. In many epidemics 

 of influenza the bacillus has not been isolated, or success has obtained 

 in only a small proportion of the cases. The influenza bacillus seems 

 to grow best in symbiosis with some other organism, especially with S. 

 pyogenes aureus. 



Koch-Weeks Bacillus (Koch, 1883). This produces a severe 

 conjunctivitis. It is very common in Egypt and is also a frequent 

 cause of conjunctivitis in the Philippines and in temperate climates. 



Smears made from conjunctival secretion show large numbers of 

 small Gram negative bacilli, especially contained within pus cells, 



