234 BACTERIOLOGY FOR NURSES 



vidual to another or indirectly by the use of objects contami- 

 nated with fresh secretions since the organism is so feebly resistant 

 to influences outside of the body, and it is present in enormous 

 numbers in the secretions of the respiratory tract. Carriers may 

 be responsible for the cases which appear sporadically and for the 

 commencement of epidemics. 



Immunity. No apparent immunity seems to be conferred by 

 an attack of the disease ; in fact, one attack seems to predispose 

 to subsequent attacks. Nor has a serum been produced which 

 could be used for the production of passive immunity; vaccine 

 treatment has been said to have been of benefit. Its value, how- 

 ever, has not yet been fully confirmed. 



KOCH-WEEKS BACILLUS 



The organism was first observed by Koch in 1883 while in Egypt, 

 and later in 1887 it was more fully described by Weeks in New 

 York, who obtained it in cultures growing with B. xerosis from cases 

 of " pink eye " or acute contagious conjunctivitis. The bacillus 

 is closely similar to the influenza bacillus ; the relationship has not 

 yet, however, been determined. Recent studies indicate that 

 the Koch- Weeks bacillus may be a strain of the influenza bacillus. 



Several similar hemoglobinophilic organisms have been de- 

 scribed in pathological conditions of the eye. In 1896 Morax and 

 later Axenfeld isolated the Morax-Axenfeld bacillus from cases 

 of subacute inflammation of the eye. Zur Nedden found a similar 

 bacillus known by his name in certain ulcers of the cornea. 



BACILLUS PERTUSSIS 



Bordet and Gengou in 1906 were the first to describe an organism 

 resembling the influenza bacillus which appears in enormous 

 numbers in the sputum of cases of whooping cough and to which 

 they gave the name B. pertussis. 



Morphology and Staining. The bacillus is a short, somewhat 

 oval rod, usually appearing singly, but occasionally in pairs joined 



