100 Kansas Academy of Science. 



bouillon is then filtered, and the filtrate, which contains the 

 toxin, is then used in producing the immunity. At first a very 

 small amount of diluted toxin is injected into the horse. After 

 it recovers from this inoculation a second larger and more 

 virulent injection of toxin is introduced. Recovery from this 

 second is followed by a third injection of still larger propor- 

 tions, and so on until the horse reaches the desired immunity. 

 Then a certain amount of blood is drawn from it. The serum 

 which contains the antitoxin bodies is separated off from the 

 other elements of the blood and distributed as diphtheria anti- 

 toxin. 



Of the inestimable value of Roux and Yersen's contribution 

 little need be said, for the majority of us remember the extreme 

 apprehension caused by diphtheria epidemics prior to 1896, 

 when Roux and Yersen gave antitoxin to humanity. In those 

 days diphtheria and death were almost synonymous terms. 

 Especially severe was this disease in such cities as Paris, 

 Odessa and Rome. When some little member of the household 

 began to show signs of the development of the false membrane 

 in the throat, it was led away by an officer of the law to some 

 isolation hospital. The fond parents had little upon which to 

 base any hope of its being brought back to them in life. As- 

 suredly Roux and Yersen have robbed diphtheria of its horrors. 



XV. PNEUMONIA AND INFLUENZA. 



Another representative pathogenic bacterium is the pneu- 

 mococcus, which is the chief etiological factor concerned in 

 pneumonia. In old age especially is the disease almost invari- 

 ably fatal. The longer one lives the greater are the chances 

 that pneumonia will usher one out of this world of action. Ef- 

 forts, and with some degree of success, are being made to de- 

 velop a vaccine both for the prevention and cure of pneumonia. 

 If this is successfully accomplished the span of life should be 

 materially increased. 



The bacillus responsible for influenza or la grippe was iso- 

 lated by Pfeiffer in 1892. Great pandemics of this disease have 

 been recognized since the sixteenth century. There were four, 

 with their succeeding epidemics, during the last century. The 

 last pandemic seems to have begun in the East. According to 

 Osier, it prevailed in Buchara in May, 1889. It reached Mos- 

 cow during the following September, St. Petersburg in October, 



i 



