MORPHOLOGY OF BACTERIA 



21 



any of the lower bacteria contain true nuclei does not seem 

 to be positively determined. 



Capsule. Many bacteriologists believe that all of the 

 lower bacteria are surrounded by a gelatinous like sub- 

 stance or envelope which is designated a capsule. The cap- 

 sule, in the form in which it is recognized, consists of an 

 inner somewhat dense portion immediately surrounding the 

 body of the organism and gradually becoming thinner in 

 the outer zone. This capsule is not colored by the ordinary 

 staining processes. In stained preparations of bacteria hav- 

 ing pronounced capsules such as Micococcus lanceolatus 

 and Bacillus viscosus, the bodies of the bacteria are stained 



Fig. 8. Figures illustrating the different arrangement of 

 flagella. a, b, and d polar; c and e peritrichial. 



and surrounded by a zone which is unstained. The thick- 

 ness and form of the capsule vary in different species. Its 

 demonstration is frequently of much assistance in making a 

 rapid diagnosis. This is especially true with Micrococcus 

 lanceolatus in preparations made from a pneumonic lung of 

 an infected rabbit and in some of the higher forms such as 

 Saccharomycosis farciminosis, the cause of epizootic lym- 

 phangitis in horses. It is of further interest to note that the 

 capsule can rarely be detected about bacteria excepting 

 when they grow in the animal body or in smear prepara- 



