ALTERATIONS IN THE MOTHER-CELL. 



61 



Soon after spore formation has terminated, the membrane of 

 the mother-cell is dissipated, swelling up and dissolving in the 

 surrounding liquid, and thus leaving the spore free. This is the 

 ordinary course, but in many instances deviations occur, one of 

 them being in the case of the Spirillum endoparagogicum, discussed 

 rather more fully below. In this case the membrane of the 

 mother-cell encloses the spore long after the latter is mature, and 

 is still present when the spore germinates. This is described in 

 the next chapter. 



49. Alterations in the Form of the Mother-Cell. 



In many instances the mother-cell undergoes alterations of 

 form during the process of spore formation, and swelling occurs. 



When this happens at one of the polar terminations of a rod- 

 shaped cell, the latter then assumes the form of a nail or drumstick. 



FIG. 15. Vibrio rugula. 



Seven rods, each with a 

 terminal spore. (After 

 Prazmou'ski.) Magn. 



FlQ. 1 6. Clostridium butyricum. 

 Spore formation. 



a, &. purely vegetative cells ; d. commencement of 

 spore formation ; c-e. progress ; f-h. completion ; 

 a-f. contain granulose stained blue by iodine ; 

 h. devoid of this carbohydrate, unstained by 

 iodine ; g. cell with two spores. (After Praz- 

 mowski.) Magn. 1020. 



Bacteria exhibiting this peculiarity are styled nail-bacteria or 

 helo-bacteria by Billroth, or Urocephalum by Trecul; and in 

 medico-bacteriological literature they are also frequently called 

 pin-head bacteria. The earliest known example of this kind 

 was the Fibrio rugula (Fig. 15), frequently encountered in pools, 

 and another is the "drumstick bacillus," found in human faeces 

 by BIENSTOCK (I.). The author has often found morphologically 

 similar fission fungi in the skin developing on the surface of 



