SECOND TYPE OF SPORE GERMINATION. 69 



In Clostridium butyricum, Cl. Poly my xa, and a few others, 

 the spore capsule opens at one of the poles, so that the direction 

 taken by the young rod in 

 its escape is in a line with 

 its length, as shown in a Q 

 Fig. 22, d. The expulsion 

 is effected by the spore 

 membrane, the tension of 

 which is gradually in- 

 creased to such an extent, 



FIG. 22. Clostridium butyricum. 

 Spore formation. 



a. ripe spore. 

 6. ditto expanding in nutrient solution. 

 c. final dimensions attained, and separation of 

 exosporium from endosporium visible. 



through the expansion of rf ' %^^ i r aping * 



the spore contents, that it (J/*er Prazmowski.) Magn. 1020. 



finally squeezes out the 



mature spore. The capsule then shrinks at once to its original 



size, and gradually disappears from view by swelling up and 



dissolving in the surrounding liquid. If the spore has originated 



t-U. 



Note. 10 to 12 Uhr M. (U.) = 10 A.M. to 12 noon ; i to 7 U = i to 7 P.M. 

 FIG. 23. Germination of spores of Bacillus sessilis. 



Progressive observation of the germination of five endospores (1-5) under the micro- 

 scope at 3o-35 C. Hanging-drop culture in meat-extract solution. The time of the 

 observation (from 10 A.M. to 7 P.M.) is given under the illustrations of the separate stages 

 of development (A-K) of the germination. Spore 3 had not germinated even at 7 P.M. 

 (After L. Klein.) Magn. about 1000. 



from any species of motile bacteria, the liberated rod begins to rove 

 directly one of its extremities is free. 



It not infrequently happens that the empty spore capsule is 

 not completely detached from the germ, but rests as a well- 

 defined cap on the rearward pole for some time, until finally it 

 disappears. In a few species the persistence of this membrane 

 is very considerable, whilst the force of contraction is small and 

 insufficient to expel the matured rod. An example of this is 

 afforded by the Bacillus sessilis, discovered by L. KLEIN (I. and II.), 

 which as its distinctive name implies remains embedded in 

 the spore membrane. This captivity, nevertheless, in nowise 

 retards its nutrition and reproduction, since by fission it forms 



