60 BA CTER10LOG Y. 



throughout, and in consequence when germination oc- 

 curs the growing bacillus, the so-called vegetative form 

 of the organism, protrudes through the thinnest part 

 of the spore-membrane that is, through the point of 

 least resistance. This may be either the end or the side 

 of the spore, according to the species under observation. 

 In certain cases such a protrusion is not observed, but 

 in its place the spore in toto appears to be gradually 

 absorbed or in some way converted directly into a 

 vegetating cell. It evinces no motion other than the 

 mechanical tremor common to all insoluble microscopic 

 particles suspended in fluids, and it remains quiescent 

 until there appear conditions favorable to its subsequent 

 development. Occasionally the membrane of the vege- 

 tative cell in which the spore is formed does not disap- 

 pear from around it, and the spore may then be seen 

 lying in a very delicate tubular envelope. Now and 

 then, remnants of the envelope may be noticed ad- 

 hering to a spore which has not yet become com- 

 pletely free. 



By the ordinary methods of staining, spores do not 

 become colored, so that they appear in the stained 

 cells as pale, transparent, oval bodies, surrounded by 

 the remainder of the cell, which has taken up the dye. 



A single cell produces but one spore. This may be 

 located either at an extremity or in the centre of the 

 cell. (Fig. 6.) 



Occasionally spore-formation is accompanied by an 

 enlargement of the cell at the point at which the proc- 

 ess is in progress. As a result, the outline of the cell 

 loses its regular rod shape and becomes that of a club, 

 a drum-stick, or a lozenge, depending upon whether 

 the location of the spore is to be at the pole or in the 

 centre of the cell. (See Fig. 6, e and d.) 



