a b c d e 



IWT 



SPORE FORMATION 139 



(B) Cell of the parent bacillus altered in shape. 



1. Clostridium (Fig. 91, b): Rod swollen at the centre 

 and attenuated at the poles; spindle shape; e. g., B. 

 butyricus. 



2. Cuneate (Fig. 91, c) : Rods swollen slightly at one 

 pole and more or less pointed at the other; wedge- 

 shaped. 



3. Clavate (Fig. 91, d) : Rods 

 swollen at one pole and cylin- 

 drical (unaltered) at the other; 

 keyhole-shaped; e. g., B. 

 chauvei. 



4. Capitate (Fig. 91, e) : Rods FlG - 

 with a spherical enlargement 



at one pole; drumstick-shaped; e. g., B. tetani. 



The endospores remain within the parent cell for a 

 variable time (in one case it is stated that germination 

 of the spore occurs within the interior of the parent cell 

 " endo-germination ") , but are eventually set free, 

 as a result of the swelling up and solution of the cell 

 membrane of the parent bacillus in the surrounding 

 liquid, or of the rupture of that membrane. They then 

 present the following characteristics: 



1. Well-formed, dense cell membranes, which renders 

 them extremely difficult to stain, but when once stained 

 equally difficult to decolourise. 



2. High refractility, which distinguished them from 

 vacuoles. 



3. Higher resistance than the parent organism to 

 such lethal agents as heat, desiccation, starvation, 

 time, etc., this resistance being due to 



(a) Low water contents of plasma of the spore. 



(b) Low heat-conducting power 1 of the spore 



(c) Low permeability J membrane. 

 This resistance varies somewhat with the particular 



species e. g., some spores may resist boiling for a few 



