MICROBIAL DISEASES OF MAN AND ANIMALS. 637 



TETANUS.* 

 Bacillus tetani. 



This disease is found throughout the world but more frequently in 

 warmer than in colder climates. Certain localities are particularly 

 affected. Man and domestic animals are susceptible. 



The incubation period varies from a few hours in experimental in- 

 oculation of small animals, to several days or weeks in cases of natural 

 infection in man. 



The disease follows an incision of a punctured type with contamination 

 by earth, especially in wounds of hands and feet. 



It is characterized by tonic spasms of the voluntary musculature 

 usually begining in some one group of muscles and finally becoming 

 general. The parts first affected are, in cases artificially produced, those 

 at the site of inoculation, but in natural infections in man it is more common 

 for the disease to manifest itself first by stiffening of the muscles of the 

 neck and face, producing what is ordinarily termed "lockjaw." In less 

 severe infections in man local pain and stiffness are the first indications. 

 The spasms occur in paroxysms which are spontaneous or excited by 

 effort. They are more or less prolonged and exhausting and are accompa- 

 nied by greater or less pain. Death results from general loss of strength 

 or involvement of the respiratory muscles. The shorter the incubation 

 period the higher the mortality. Few recover when the incubation period 

 is less than ten days, about half the cases recover when the period is more 

 than fifteen days. 



The nerves may show injury as indicated by swelling and redness and 

 microscopically nerve cells have been observed in a state of granular 

 degeneration; there is a more or less distinct general congestion of the 

 organs. 



While lockjaw has been known clinically for centuries, it was not 

 until 1884 that the infectious character was demonstrated when Carlo 

 and Rattone and Nicolaier were successful in animal inoculations. 

 Kitasato obtained pure cultures of the bacillus in 1889. 



The organisms may be detected occasionally by examination of 

 stained preparation of the pus from the wound. Pure cultures may be 

 obtained by inoculating an alkaline dextrose broth with pus or tissue, 

 incubating under anaerobic conditions for about forty-eight hours until 



* Prepared by Edward Fidlar. 



