EXPERIMENT STATION BULLETINS 



217 



Actnal. 



Brownina. 



like motion, all of which are progiessivp, moving; from one 

 place to another. These bacteria possess actual motion. There 

 are other bacteria which have only a vibratory motion, or an 

 up and down motion, but do not move from one place to another. 

 This kind of motion is known as Brownian motion. Again, 

 there are other bacteria which remain absolutely still. 



FLAGELLA. 



Associated with actual motion in bacteria are orj^ans of propulsion, 

 called flatjella, cilia, and even whips, because they are whip-like 



CompoBition. appendages. From some of their reactions to stains, they 

 res- mble the structure of the cell wall, and may be merely a 

 continuation; yet if they really are concerned in the move- 

 ments, it would seem more plausible to consider protoplasm 



Arrangement, as part of their structure. Bacteria difPer widely in the arrange- 

 ment of their flagella. The bacillus mny have but one flat^ellum 

 or it may have numerous flagella. When possessing only one, 



it is placed afc the end, but if many, they 



radiate from all sides. In the micro- 

 coccus the whip proceeds from the side. 



Very few micrococci are known to have 



whips. The true spirilla possess a 



bunch of flagella at each end, and the 

 vibrio a single whip at the 

 end. The ordinary flagella 

 are three to ten or twelve 

 times the length of the micro- 

 organism. In a few species, 

 what are known as giant 



whips have been found which are forty 



to sixty times the length of the micro-organism, 



Size. 



Giant. 



Fig. 5. Flagella. 



SPORES. 



In the discussion of protoplasm, reference was made to its condition 

 just before the formation of the spore. It becomes granular 

 Kormation. and more refringent. The granules gradually proceed towards 

 that portion of the cell, where the spore is in process of forma- 

 tion; there they coalesce, take on a membrane or sheath and assume the 



form of a spore. This spore may be located 

 Location. at the end of the cell, at the middle, or any 



place between the middle and the end. It i^ C" 



may be wider than the cell, thus causing a 



bulging. In such a case, when the spore 



is located at the end, it will produce a club Fig. 6. spores. 



shaped or a drum stick shaped micro-organism. When the spore is in the 



middle and produces a bulging, it gives rise to the Clostridium form. 



Wherever the spore is in the cell, it undergoes about the same life history; 



As soon as the cell has produced its spore, it will begin to dis- 



Germination. integrate and eventually leave the spore free. This spore will 



not generally germinate when left in the same medium in which 



it was produced, but if transferred to a suitable medium will 



