BACILLUS DIPHTHERIA. 355 



methylene-blue, the bacilli are found to have the following 

 characters. They are slender rods, straight or slightly 

 curved, and usually about 3 /x in length, their thickness 

 being a little greater than that of the tubercle bacillus. 





' 





<* * 



\ 



~J ,g^*. 



FlG. 89. Film preparation from diphtheria membrane ; showing 

 numerous diphtheria bacilli. One or two degenerated forms are seen 

 near the centre of the field. (Cultures made from the same piece of 

 membrane showed the organism to be present in practically pure 

 condition.) 



Stained with methylene-blue. x 1000. 



The size, however, varies somewhat in different cases, and 

 for this reason varieties have been distinguished as small 

 and large, and even of intermediate size. It is sufficient 

 to mention here that in some cases most are about 3 //. 

 in length, whilst in others they may measure fully 5 yu. 

 Corresponding differences in size are found in cultures. 



