324 



BACILLI PATHOGENIC IN ANIMALS. 



dogs, diarrhoea, with at times bloody stools, and death 

 within 3 to 10 hours ; on post-mortem examination all 

 the appearances of an acute gastro-enteritis are found. 



Microscopical 

 characters. 



Bacillus pseudopneumonicus (Passet). 

 Pseudo- These organisms have been cultivated on two occa- 



pneumomc , _ , . . . ~ 



bacteria. sions by Passet from the pus of abscesses in man.* 

 They are oval or round, seldom elongated, cells resem- 

 bling hose of the pneumonia bacilli, but with a greater 

 tendency to the formation of rounded forms. Their 

 transverse diameter is *87 ^., their longitudinal I 1 16. 

 In preparations which have been taken from the animal 

 body, or from cultivations grown at the body tempera- 

 ture, the bacteria are seen to be surrounded by a sheath 

 which takes up the colouring matter. 



Cultivations. In gelatine plates white points appear after 24 hours, 

 and under a low power present the form of round, finely 

 granular, grey, and later often very dark discs, with 

 regular sharp outlines. On the surface the colonies 

 form greyish-white prominent nodules of about the size 

 of half the head of a pin ; the pneumonia colonies are 

 somewhat thicker and whiter. In puncture cultivations 

 the pseudo-pneumonia bacillus grows only on the sur- 

 face, being a pure ae'robe, and forms on the surface 

 greyish-white hemi-spherical glistening nodules ; it does 

 not grow at all along the track of the needle. On 

 blood serum it forms a thin greyish-white layer; on 

 potatoes kept at 37 C. a thick white shiny moist layer 

 appears in 24 hours, without any development of gas, 

 or formation of bubbles. In mice, rats, guinea-pigs, 

 and rabbits the injection of Passet 's bacteria into the 

 pleura causes pleuritis, and into the abdomen, peri- 

 tonitis ; subcutaneous inoculation kills mice from 

 septicaBmia, but as a rule only causes the formation of 

 abscesses in rats, guinea-pigs, and rabbits ; 43 mice 

 treated by inhalation of the cultivations remained well. 



* They are described by the author as cocci, but on account of the 

 analogy with the pneumonia bacteria, and for the reasons given with 

 regard to the latter, these organisms have been included here under 

 the bacilli. 



Experiments 

 on animals. 



