II 



■0 



When a bacterium is round in shape it is known 

 as a " coccus," and if very small as a " micrococcus " : 

 cocci occurring in pairs receive the name of " diplo- 

 cocci " : those cocci that are found to arrange them- 

 selves one after another like a chain are called 

 " streptococci," and those that form groups after the 

 manner of a bunch of grapes are distinguished as 

 " staphylococci." 



The term "bacillus" is applied to a bacterium 

 that is rod-shaped, as opposed to the spherical coccus. 

 These vary a good deal both in size and shape ; they 

 may be short and thick like the septic bacillus or long 

 and thin like the one responsible for (the real) tuber- 

 culosis. They may have round ends or square ends ; 

 they may stain throughout or only at the ends ; in 

 short the differences are endless not only between 

 species but even in a less degree between individuals 

 of the same species. 



In addition to cocci and bacilli there are many 

 other shapes in which bacteria are found, but the 

 above enumeration will be enough for our purpose, 

 and I fear to weary my readers with too many 

 technicalities. 



Among other w^onders connected with these 

 marvellous organisms their minuteness is not the 

 least. They are so small as to necessitate the use of 

 a specially adopted term of measurement— the micron, 

 representing ^ of an inch and designated by the 

 sign fx. Many microbes measure but .5^ and there are 

 but few that reach 2.5/x. 



(To be con tinned. J 



