DIPHTHERIA 159 



DIPHTHERIA. 



Discovery and morphology of the organism — Growth on media — Bac- 

 teriological diagnosis — Method of staining — Other organisms accom- 

 panying diphtheria — Distribution and occurrence — Pathogenesis — 

 Antitoxin treatment — Preparation of the antitoxic serum — Besults 

 and advantages of the treatment — Dr. Washbourn's report upon the 

 serum treatment — Practical disinfection. 



The bacillus causing diphtheria was first described by 

 Klebs in the year 1875, but was not universally regarded 

 as the true cause of the disease till Loffler succeeded in 

 obtaining pure cultures in the year 1884. The Klebs- 

 Loffler bacillus is a short rod devoid of motility, sometimes 

 apparently pear-shaped at the ends when stained. When 

 grown from the throat in the early stage of the disease, the 

 organism is usually seen as a short rod, about 3 fi long 

 and 1 fjL thick ; but after subculturing through several genera- 

 tions, it grows out into rods twice this length and thick- 

 ness ; the protoplasm then often takes the stain unevenly. 



When specimens are examined from a case in which the 

 patient suffered from true diphtheria and is now con- 

 valescent, it is generally found that the bacilli are pi-esent 

 as long and short rods together. The bacillus does not 

 form spores, but is not killed by drying ; dust containing 

 the bacillus retains its virulence for months. The organism 

 is aerobic, and its thermal death-point is 58° C. 



Growth on Media. — The bacillus grows readily on gelatine, 

 if slightly alkaline, but more rapidly on agar at blood-heat, 

 but the colonies so produced have no special characters. 

 On potato there is hardly any visible growth, unless the 

 potato be first moistened with beef-broth, in which case the 

 growth is both rapid and visible. 



On blood serum or glycerine-agar it grows with great 

 rapidity, but the best medium of all is that devised by Loffler, 

 who uses equal parts of serum and broth, with 8 per cent. 



