422 BACILLI WHICH PRODUCE SEPTICAEMIA 



evaporation and desiccation a funnel-shaped cavity is formed in the 

 culture medium in the course of two or three weeks. In gelatin 

 plates colonies are developed in the course of two or three days in the 

 deeper layers of the gelatin, but not upon the surface ; these are ne- 

 bulous, grayish-blue, radiating masses, which are so delicate as to be 

 scarcely visible without the aid of a lens or a dark background. 

 Under a low power they appear as branching, feathery masses, which 

 have been compared by Fliigge to the radiating growth of " bone 

 corpuscles." In older cultures they coalesce and 

 cause a nebulous opacity of the whole plate, which has 

 a bluish-gray lustre. 



Upon the surface of nutrient agar or blood serum 

 a very scanty development occurs along the line of 

 inoculation. No growth occurs upon potato. In 

 bouillon the bacilli cause a slight cloudiness at the 

 mia; single colony outset, and later a scanty, grayish- white deposit upon 



x 80 Utr (Fm g |o tm ' tnebottom of the test tube ; no film is formed upon 

 the surface. 



The thermal death-point of this bacillus, as determined by the 

 writer (1887), is 58 C., the time of exposure being ten minutes. In 

 the experiments of Bolton it was destroyed in two hours by mercuric 

 chloride solution in the proportion of 1 : 10,000 ; by carbolic acid and 

 by sulphate of copper in one-per-cent solution. These results are 

 opposed to the view that the minute refractive granules which may 

 sometimes be seen in the interior of the rods are reproductive spores, 

 for all known spores have a much greater resisting power to heat 

 and the chemical agents named. 



PatTiogenesis. Pathogenic for swine, rabbits, white mice, house 

 mice, pigeons, and sparrows. Field mice, guinea-pigs, and chickens 

 are immune. 



Swine may be infected by the ingestion of food containing the 

 rothlauf bacillus, as has been demonstrated by allowing them to eat 

 the intestine of an animal which had recently succumbed to the dis- 

 ease, and also by the subcutaneous injection of pure cultures. The 

 disease usually terminates fatally within three or four days, and 

 sometimes in less than twenty -four hours. It is characterized by 

 fever, debility, loss of appetite, and by the appearance upon the sur- 

 face of the body of red patches, which gradually extend and become 

 confluent, producing after a time a uniform dark-red or brown color 

 of the entire surface. The discharges from the bowels frequently 

 contain bloody mucus. At the autopsy, in acute cases, the spleen is 

 notably enlarged, and the liver and kidneys are likely to be more or 

 less swollen, as are also the lymphatic glands, especially those of 

 the mesentery; the gastric and intestinal mucous membranes are 



