68 BACTERIOLOGY 



sary. Peculiar degeneration forms are often seen, both in films 

 from the throat and from cultures, the most characteristic 

 being an Indian-club-like swelling of one end of the bacillus 

 (see Frontispiece, fig. 10). The bacillus is a very hardy one, 

 and will live for a long period when dried. It does not, how- 

 ever, produce spores. 



Diphtheria toxin and antitoxin. The toxins of the diph- 

 theria bacillus may be artificially prepared by filtering a broth 

 culture, suitably grown, the resulting germ-free fluid contain- 

 ing the highly-poisonous products of the bacillus. This fluid 1 

 may be used for experimental work upon animals, for example 

 for the production of active immunity in horses (see p. 48), 

 the resulting serum being prepared in large quantities com- 

 mercially and sold for therapeutic and prophylactic use as 

 "Anti-diphtheritic serum" or "Antitoxin." It must be used 

 as early as possible in the disease, and in sufficient quantity, 

 and, especially in serious cases, must be injected frequently. 

 Since its introduction, there has been a remarkable diminution 

 in the death-rate from diphtheria. There is usually rapid 

 improvement of the case unless the treatment has been 

 commenced too late with casting off of the false membrane, etc. 

 Local antiseptic treatment of the throat must also be thoroughly 

 carried out. In cases where the bacillus persists in the throat 

 during or after convalescence, vaccine-treatment, or this com- 

 bined with the use of the antitoxin, may bring about its 

 disappearance, though in some cases it is extremely persistent. 

 Another point of importance is that certain paralytic lesions 

 may follow diphtheria, due to the poisonous action of the 

 toxins on the nervous system. These are not always prevented 

 by the use of antitoxin. Many more cases now survive the 

 disease because of antitoxin treatment, and any apparent increase 

 in the number of such cases of post-diphtheritic paralysis is 

 due to the fact that in the old days such patients would have 

 died instead of surviving and showing this phenomenon. 



Bacillus mallei. Glanders or Farcy is a disease especially 

 of horses, mules, and donkeys, and is transmissible to certain 

 other animals and to man, and also to laboratory animals, 

 especially guinea-pigs. It may be acute or chronic, and in 

 horses and other equines, the disease usually starts with in- 

 flammation and ulceration of the mucous membrane of the 

 nose. From this position it tends to spread along the lymph- 

 atic channels and to the lymphatic glands of the neck, producing 



1 A very virulent strain of B. diphikeriae may produce enough toxin in 

 a single cubic centimetre of the fluid to kill off a thousand guinea-pigs. 



