FORM AND STRUCTURE OF BACTERIA 2Q 



micron in length and 0.06 micron in width. Bacillus 

 dentrificans Mig. is a rod i to 1.5 microns in length by o.i 

 to 0.3 micron in width. The Micrococcus progrediens 

 (Schroter) is 0.15 micron in diameter. A bacterium de- 

 scribed by Nocard and Rouxin pleuropneumonia is said to 

 be still smaller. Without doubt there are still smaller organ- 

 isms which are ultramicroscopic. Some of the largest 

 bacteria have been reported by Errera and Schaudin. They 

 describe a spirillum of the dimensions 23 to 28 microns in 

 length by 3 to 3.4 microns in width, and also a bacillus 24 

 to 80 microns in length and 3 to 6 microns wide. Some very 

 large cocci have been reported by various writers. 



Fischer makes the estimate that it would take 30,000,000,000 

 pus cocci to weigh one gram. In a drop of water one cubic 

 centimeter in size 1,700,000,000 pus cocci would have plenty 

 of space. Bujwid counted the number of Micrococcus 

 pyogenes var. aureus cells in a milligram of a pure culture and 

 found that there were approximately 8,000,000,000. Fischer 

 states that if an anthrax bacillus is 3 to 10 microns long and 

 i to 1.2 microns broad, that 8,000,000, at least, would be 

 required to equal a mass the size of an ordinary cigarette. 

 Nageli gives the weight of an average bacterium as 

 a io,ooo,ooo,oooth part of a milligram. 



Locomotion of Bacteria 



Flagella. Certain species of bacteria possess the power 

 of locomotion. The degree of motion depends upon the age 



