D/rilTHERIA. 



147 



organism which bears their combined name Klebs-Loeffler. 

 Indeed, no infections disease has been better studied from its 

 etiological and therapeutical standpoints than diphtheria, and 

 it conforms absolutely to the postulates of Koch before men- 

 tioned : that is, it is found in animals sick with the disease, 

 it may be cultivated artificially, and pure cultures inoculated 

 into susceptible animals produce the disease. The disease is 

 not produced by any other germs, and besides injection of its 

 toxins produces in animals substances which are of immu- 

 nizing value when injected into susceptible animals. 



FIG. 56. 



FIG. 57. 



One of very characteristic forms of 

 diphtheria bacilli from blood-serum 

 cultures, showing clubbed ends and ir- 

 regular stain. X 1100. Stain, meth- 

 ylene-blue. (Park.) 



Extremely long form of diphtheria 

 bacillus. This culture has grown on 

 artificial media for four years and pro- 

 duces strong toxin. X 1100. (Park.) 



The Bacillus diphtherice is found a. in false membranes of 

 diphtheritic origin ; b. occasionally in the mouth and nose of 

 healthy individuals ; and c. in the dust of rooms inhabited 

 by diphtheritic patients, or on articles of clothing or furniture 

 which, though they may not have come into direct contact 

 with the patients, yet have been in the same room with them. 



Morphology. The Klebs-Loeffler bacillus is a short rod, 

 from 2 to 6 mikrons in length, and from 0.2 to 0.8 mikron 

 in breadth, being found longer in certain cultures than in 

 others, and when grown for several generations in artificial 

 media The rods occur singly or in pairs, or in irregu- 



