BACILLI OF THE COLON. 67 



are the agglutinins which gather the bacilli together 

 into clumps. The agglutinins caused by infection with 

 the colon bacillus will agglutinate only the colon 

 bacillus ; the same is true for the typhoid, paratyphoid, 

 and dysentery bacilli. This peculiarity is made use of 

 in diagnosing the kind of infection present. 



THE Mucosus CAPSULATUS GROUP. 



In this group are placed a number of micro- 

 organisms which resemble one another closely in their 

 morphology and manner of growth. The members of 

 this group differ but little from those of the colon 

 group. 



THE BACILLUS Mucosus CAPSULATUS. 



This bacillus was discovered by Friedlander in 

 1883, and is often called the Friedlander bacillus. It 

 is a short, plump bacillus, with rounded ends, exhibit- 

 ing considerable variation in size. It may occur 

 singly, in pairs, or in chains. It is not motile and 

 forms no spores. On all the ordinary culture media it 

 grows readily even at room temperature. The most 

 characteristic feature is the transparent capsule about 

 the organism. Exposure to heat of 60 C. destroys 

 the bacillus in a short time. 



At the time of its discovery this bacillus was be- 

 lieved to be the chief cause of lobar pneumonia, but 

 it has since been proved that it is responsible for only 

 a small percentage of the cases. In addition to caus- 



