Man and Microbes. 97 



ished. It is said that at the siege of Gaffa, in Crimea, by the 

 Tartars, 1346, the city appeared impregnable. In the mean- 

 time plague broke out among the besiegers, and to them ap- 

 parently the city was lost. Suddenly it occurred to one of the 

 besieging generals to throw into the defiant city, by means of a 

 catapult, a dead victim of plague. The disease spread like 

 wildfire among the besieged. This act alone caused the fall of 

 Gaffa, and from there the plague was carried to Constanti- 

 nople by the escaping besieged. 



At present there still exists the smoldering remnants of the 

 third epidemic of plague which originated in China in 1871. 

 From there it spread to India, where 6,000,000 natives died 

 within the period of ten years. It has appeared in the prin- 

 cipal seaports of the world since then. Only two years ago it 

 appeared in New Orleans. The vigilant activities . of the 

 United States Public Health Service soon stamped it out. 



Plague is primarily a rat infection, and is transferred from 

 this animal to man by the flea. Eradication of these two* 

 carriers will assure man's freedom from this fatal infection. 



XIV. DIPHTHERIA AND TETANUS. 



The decade following 1880 was remarkable for the dis- 

 covery of many of the important pathogenic bacteria. In 1883 

 Klebs found in the false membrane of the throats of children, 

 who had been choked to death from the extremely prevalent 

 and dreaded infection known as diphtheria, the specific germ 

 responsible for the disease. The year following Loefller found 

 that he could produce the disease in rabbits and guinea pigs. 

 He learned, however, that it was first essential to abraid or 

 scarify the mucous membrane of the throats before the ani- 

 mals would contract the disease. A noteworthy observation 

 this was, for from it we have learned of the dangers of colds. 

 Colds, like the experimental scarification of Loeffler's, break 

 the continuity of the protective mucous membrane and permit 

 other dangerous germs to gain entrance into the system. 

 Therefore, a cold may be the forerunner of tuberculosis, scar- 

 let fever, diphtheria or other serious and fatal infections. 



During the time that Klebs and Loeffler were busy with ex- 

 periments regarding the diphtheria bacillus and its habits. Von 

 Behring and Kitasato isolated the peculiar drum-stick-like ba- 

 cillus which is responsible for lockjaw or tetanus. This germ 



7— Sci. Acad.— 2163 



