IN SUSCEPTIBLE ANIMALS. 445 



developed in the course of two or three days in the deeper layers of 

 the gelatin, but not upon the surface ; these are nebulous, grayish- 

 blue, radiating masses, which are so delicate as to be scarcely visi- 

 ble 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 Flugge 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 

 outset, and later a scanty, grayish- white deposit upon the bottom 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. 



Pathogenesis. 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 

 usually inflamed and spotted with hsemorrhagic extravasations ; the 

 serous membranes also may be inflamed, and the cavities of the 

 pleura3, pericardium, and peritoneum usually contain more or less 

 fluid. The bacilli are found in the blood vessels throughout the 



