128 SPECIAL BACTERIOLOGY 



and irregular edges develop at first, from which brush-like offshoots are 

 thrown out. Other colonies are surrounded by a zone of threads which, 

 partly in circular, partly in irregular twisted forms, surround the central 

 opaque mass. The gelatine is quickly liquefied. Straight and twisted 

 offshoots, which frequently become detached from the mother-stem, grow 

 into the surrounding medium, and continue moving in the somewhat 

 softened gelatine. This condition is known as Swarming Islands (see 

 Photomicrograph of same, Fig. 45), which is easily observed in cultures 

 on 5 to 6 per cent, gelatine. Peculiar figures and designs also occur, 

 whereby the proteus has been designated the Bacillus Jtgurans. 



Stab Cultures in gelatine liquefy very quickly. 



On oblique surface Agar a rapidly extending moist grey layer is 

 formed. 



On Potatoes a dirty greyish coating develops. 



Bouillon becomes uniformly clouded. Cultures on all the different 

 media give off an abominable smell. 



Pathogenesis. When a considerable quantity of a proteus culture 

 (3 c.c.) is injected intravenously or into the peritoneum of a rabbit or 

 guinea-pig, the animals die of acute enteritis and peritonitis. The intra- 

 venous injection of 5 to 10 c.c. of a bouillon culture in dogs causes more 

 typical symptoms and lesions. The symptoms produced are bloody 

 vomiting and diarrhoea, combined with severe tenesmus and elevation of 

 the temperature. At the autopsy an intense haemorrhagic enteritis is 

 found. The blood and internal organs either contain none or very few 

 bacilli. With filtered cultures and with cultures containing the remains 

 of dead bacilli, the same results are obtained. The proteus is also fatal 

 to mice, and the bacilli can again be cultivated from their organs, and 

 the more often the bacillus is passed through mice the more virulent it 

 becomes. 



The proteus bacteria are found in all putrefactive processes, and in 

 the intestinal canal. In man the proteus forms a mixed infection with 

 the ordinary exciters of inflammation. They cause the ichorous, putrid 

 phlegmon sometimes observed in cases of cadaveric infection. The 

 proteus, further, sometimes penetrates suppurating wounds, and increasing 

 these, forms toxic products which, when absorbed, cause the so-called 

 ' putrid intoxication.' According to H. Jager, certain forms of icterus, 

 accompanied with fever, pain in the muscles, and enlarged liver and 

 spleen, known as ' Weil's disease,' are produced by the proteus. Jager 

 was able to cultivate from the urine, and after death, from the organs of 

 individuals dead of Weil's disease, a fluorescent proteus. The infection 

 resulted in these cases from bathing in river-water which was con- 

 taminated with the proteus. An outbreak of disease due to the proteus 

 fluorescens also occurred among some poultry kept on the banks of a 

 small stream. 



