MORPHOLOGY OF BACTERIA 25 



germination the first change observed is that the spore 

 swells up and lengthens, due probably to the absorption of 

 moisture. As the spore enlarges it becomes less refractive 

 and dull in appearance. It then gives rise to a young organ- 

 ism in one of three ways. 



1. Direct germination, in which the spore gradually 

 -changes by elongating and growing directly into an organ- 

 ism. In this case no shell or spore wall is thrown off, 

 although it may possibly be softened and dissolved during 

 the process of conversion. 



Usually in spore germination the spore wall splits open 

 at some one place on the surface and through the opening 

 thus produced a young form makes its appearance. When 

 the opening in the spore wall is at the end of the elongated 

 spore it is spoken of as polar and when in the middle it is 

 designated equatorial. 



2. Polar germination. In this form the elongated spore 

 opens at one pole and the young cell grows out of the spore 

 wall. The long axis of the new organism is parallel to the 

 long axis of the spore. The anthrax spore germinates in 

 this way. 



3. Equatorial germination. In this form the length- 

 ened spore opens as a result of a split across the middle. In 

 .some species the spore wall is completely divided and the 

 two walls are pushed asunder by the young spore. In the 

 case of Bacillus subtUis the cleft is incomplete. In such 

 instances the young rod-shaped organism leaves the spore 

 wall either by doubling up and assuming a horse shoe form 

 or it rotates and passes out at right angles to the axis of the 

 spore. 



Conditions necessary for spore germination. In the ger- 

 mination of spores in disease producing bacteria it is neces- 

 sary to have in addition to a suitable culture medium or 

 soil, proper temperature. The process takes place slowly in 

 a low temperature and more rapidly in a temperature nearer 

 that of the animal body. 



