PATHOGENIC BACTERIA. 285 



with the pseudo-membranous inflammations of the intestines 

 and bladder. Although such inflammations are often called 

 " diphtheritic," it must be remembered that the expression 

 is used in an anatomical sense, meaning that a fibrinous 

 pseudo-membrane has formed, extending deeply into the 

 tissues, which is not necessarily caused by the diphtheria 

 bacillus. 



In cases of diphtheria in man, 1 the diphtheria bacillus is 

 generally found limited to the vicinity of the pseudo-mem- 

 brane, and at autopsies it is not usually found in the in- 

 ternal viscera, excepting in the lungs, where diphtheria 

 bacilli may or may not be present when diphtheria is com- 

 plicated with broncho-pneumonia. The general symptoms 

 of the disease, including the paralysis which sometimes 

 follows it, are due to the toxins produced by the bacilli in 

 the throat. 



Diphtheria antitoxin. It is necessary first to obtain the toxin pro- 

 duced by diphtheria bacilli in a concentrated form. Virulent diphtheria 

 bacilli are cultivated in alkaline bouillon, in flasks plugged with cotton, 

 exposing a large surface to the air. The cultures are grown in the 

 incubator. After five to ten days they are ready, and are filtered through 

 porcelain. The filtrate contains the toxin. The animal usually em- 

 ployed is the horse, which should be healthy; the presence of tubercu- 

 losis and glanders should have been excluded, testing with tuberculin 

 and mallein ; tetanus should also be considered, see page 272. The toxin 

 is injected into the horse in small doses about i c.c. of the filtrate from 

 the bouillon culture. The dose depends on the strength of the toxin. 



The injection is repeated at intervals of about one week, using larger 

 and larger doses, until the animal is able to tolerate a very large dose 

 indeed as much as 300 c.c., or even more. If the treatment is suc- 

 cessful the general condition of the animal should not suffer. The 



1 For a full study of the lesions of diphtheria see the Monograph of 

 Councilman, Mallory and Pearce, Boston, 1901. 



2 See articles by Park, A. Williams, Atkinson and T. Smith, Journal of 

 Experimental Medicine, Vol. I., p. 164; Vol. III., p. 513; Vol. IV., pp. 

 373 and 649; Journal Medical Research, Vol. IX., p. 173. 



3 W. H. Park adds 10 per cent, of a 5 per cent, solution of carbolic acid 

 to kill the bacilli, and filters through paper on the following day; after 

 adding carbolic acid the Berkenfeld filter may be used with advantage 

 instead of filter-paper. 



