BACTERIUM XEROSIS. 417 



pathogenic properties of these organisms that they cause 

 the death of the animal in less than twenty-four hours 

 with marked inflammatory reaction affecting the perito- 

 neum as well as the abdominal organs. 



The morphologic and biologic characters of some 

 members of the group of bacterium pseudodiphtheriticum 

 are very closely allied to those of bacterium diphtheria}. 

 Other members of the group, however, are readily dif- 

 ferentiated from bacterium diphtherias by either the 

 morphologic or the biologic characters, or by both. Many 

 of the members of the group produce very little acid 

 when grown in carbohydrate media, and the slight 

 degree of acidity produced is frequently obliterated by 

 a marked degree of alkali production. This fact is of 

 special value in the differentiation from bacterium diph- 

 therias. 



BACTERIUM XEROSIS (NEISSER AND KUSCHBERT), 

 MIGULA, 1900. 



Synonym : Bacillus xerosis, Neisser and Kuschbert, 1883. 



Another organism which is also related in its mor- 

 phologic and biologic characters to bacterium diphtheria 

 is bacterium xerosis, first encountered by Kuschbert and 

 Neisser in xerosis of the conjunctiva, and which has 

 since been found on the conjunctiva by a number of 

 investigators, in various diseases as well as in health. 



The xerosis bacteria are less likely to be mistaken for 

 bacterium diphtherias because they are somewhat smaller 

 and have less tendency to show multiple striations. 

 Usually they stain deeply at the poles with only one 

 clear unstained band in the centre. It is only occa- 

 sionally that a few striated organisms are encountered 

 in a culture. 



27 



