70 THE GERMINATION OF THE ENDOSPORE. 



new rods which it protrudes through the polar openings at both 

 extremities in the muff-shaped capsule, the said rods quickly 

 forming spores in turn. An illustration is given in Fig. 23. 



58. Third Type. 



In Bacillus suUilis (Fig. 24), Bacillus megatherium (Fig. 25), 

 and a few other species, the spore membrane does not burst at 

 the poles, but along a line coinciding with the equator of the 

 spore. This line, however, extends only part of the way, not 



**! 



FIG. 24. Bacillus subtilis. 

 Spore germination. 



a. ripe sp6re ; 6. placed in a nutrient solution, 

 the refraction disappears ; c. enlargement 

 begins ; d. the equatorial fissure is formed 

 and the young germ begins to escape ; 

 e. in the upper row the central portion of 

 the germ is just protruding, in the lower 

 row one pole is already freed ; /. the 

 young rod is at liberty ; g. it grows to its 

 normal size ; h. reproduces by subdivision. 

 Extra long cells are seen at g and h in 

 the lower row. (After Prazmowski.) 

 Magn. 1020. 



FIG. 25. Bacillus megatherium. 

 Spore germination. 



ft*, two dried ripe spores enclosed 

 by the walls of the mother- 

 cell. 



ft 2 , the same spores after forty- 

 five minutes' immersion in a 

 nutrient solution. 



k, I. the spore contents have in- 

 vested themselves with a new 

 membrane and are escaping 

 from the old capsule. 



in. two full-grown rods. 

 (After De Bary.) Magn. 600. 



right round the spore, so that the two halves of the membrane 

 still remain attached together at one point. The rod then makes 

 its exit by bending somewhat at the centre, and, by turning one 

 of its extremities, pushes it out of the capsule, one half of which 

 often remains on the other pole for some time like a cap, the 

 other half hanging down empty. Sometimes the germ cannot 

 liberate even one end from the capsule, both poles remaining 

 wedged between the two halves of the membrane (these acting 

 like a pair of tongs), and the central portion alone projecting. This 

 position, however, does not prevent reproduction, but gives rise 

 to horse-shoe chains (Fig. 26), which only separate into their indi- 

 vidual members when the spore membrane has become swollen 

 and flaccid. 



The time occupied by Bacillus subtilis in germinating is, 

 according to Prazmowski, generally 3-4^ hours at 3o-35 C., 

 but frequently much longer. 



