122 THE ACUTE SELF-LIMITED INFECTIONS 



dehyde or carbolic acid solution is to be injected into the body 

 entrances and applied about the body on the winding sheet. 



For diagnosticating this disease an abscess is punctured, 

 the pus withdrawn, and slide smears and cultures are made. 

 The bacilli are found in countless numbers. Cultivation on 

 ordinary media is simple. A blood culture will also reveal 

 their presence. At death bacteria will be found in practically 

 every organ in the body. In the pneumonic form an examina- 

 tion of sputum reveals enormous numbers of the character- 

 istic organisms. 



The plague bacillus is a short plump rod, 1 7 Q 00 to 3 Q 00 

 inch long by 50 Q 00 to 30000 inch wide. It does not move 

 nor form spores. It grows best at 35 C. or 92 F. It is 

 stained with reasonable ease, displaying a peculiar picture. 

 The bacilli are short, thick rods with rounded ends. The end 

 section stain much more densely than the middle part, called 

 bipolar staining. These rods may grow longer and appear 

 in pairs or short chains. They are killed by 60 C. or 142 F. 

 in ten minutes, or by boiling water in two minutes. They 

 resist drying for two or three days under natural conditions, 

 but when drying is hastened by artificial means, they live 

 only a few hours. They resist cold and freezing for a long time, 

 perhaps a month. Sunlight destroys them in five hours. In 

 pus or sputum they may live a few weeks, but in cadavers 

 they have been found after several months. Chemicals 

 kill them as follows: 5 per cent, carbolic acid and 1 to 1000 

 bichloride in ten minutes. Animals are usually susceptible 

 to Bacillus pestis, particularly guinea-pigs and rats, and it is 

 said that simple rubbing of the germs on the skin of these 

 beasts will produce the infection. It is similar to the human 

 disease. 



Plague Serum. The poison of Bacillus pestis is largely 

 intracellular. It has been possible to get an antiserum from 

 horses which will destroy the bacteria and can be used thera- 

 peutically. The bacteria grown in the laboratory are killed 

 by moderate heat and injected into animals. The injections 



