iY OF IJACTKIIIA 



17 



spore is ultimately set free. Spore formation is virtually 

 limited to a few of the bacilli, and does not occur as long as 

 nutritive conditions admit of vegetative reproduction. It 

 is Mimnlated by lack of food or by the accumulation of by- 

 products of cell activity, rnfavorable temperat nre condi- 

 tions fm- oTowth tend to prevent th;' formation of spores. 

 It i- a specialized function of the organism, and. like most 

 such functions, occurs within a narrower range of condi- 

 tions than does reproduction. 



The diameter of the spore in some sp.-cies is greater than 

 that of the coll itself, thus producing a distortion of the 

 cell. In the case of />'. t<f<nii, the organism causing lock- 

 jaw, the enlarged spore 

 is at the end of the cell 

 forming a drumstick, in 

 which case it is call -d 

 ciipitiiti . If the spore 

 is centrally located, giv- 

 ing to the cell a 'spin- 

 dle-like appearance, it 

 is called a rloxtri<tinni 

 type. The spores are 

 readily differentiated 

 from the cell proper by 

 their higher refractile 

 power, which gives them 

 the appearance of bright 

 dots under the micro- 

 scope. In stained preparations they still appear as bright, 

 unstained spots in the stained cfells, since they do not take 

 the stain in the ordinary methods of treatment. 



The bacterial spores possess greater powers of resistance 

 to various physical and chemical agents than any other 

 form of life. They are especially resistant to heat. Some 



Fig. 8. Spores 



The unstained body to be noted in most . of 

 the cells is a spore formed by the condensa- 

 tion of a portion of the cell content 

 After Giinther. 



