CRYPTOGAMS 



333 



Multiplication of the individual is accomplished vegetatively by 

 the active division or fission of the cells ; the preservation and dis- 



l-'h.. _' ">_'. Types c.l' arrangement of Hagclla. . 

 1'ihrin I'lo'li,'" ; n, il, fi-]iii'!/ln HI n mini" ; il, 

 development of a new bunch of <-ilia in divi- 

 sion ; ', Ihicilflix l/li'lti', i. liiirillli* siilitili*. 

 (After A. FISCIIKK, X 22">0.) 



Fio. 253. Cladothrix dldwtoma. Formation 

 of swarm cells from the cells of the lila- 

 nient. (After A. FISI-HKK, x 1000.) 



tribution of the species by the asexual formation of resting spores. 

 These arise as endospores (Figs. 254 c, 256 e, /) in the middle or 

 at one end of a cell by the inner portion of the protoplasm separat- 

 ing itself from the peripheral, , 

 and surrounding itself with 

 a thick membrane. The 

 membrane of the mother cell 

 becomes swollen and disin- 

 tegrated when the spore is 

 ripe. Spores are not found in 

 all species. 



Bacillus sitbtilis, the Hay bacillus 

 (r'ig. 25-i), which appears as a rule 

 in the decoction obtained by boiling 

 hay in water, will afford an example 

 of the life-history of a Bacterium. 

 The spores of this species, which 

 withstand tin- clfect of the boiling 

 water, produce on germination rod- 

 shaped swarming cells with cilia 

 on all sides ; these divide and may 

 remain connected in short chains. 

 At the surface of the fluid these 

 swarming cells change into non- 

 motile cells without cilia, which 

 divide up, giving rise to long in- 

 tertwined chains of cells. These 

 are associated together in tlie pellicle covering the surface (zoogloea stage). Spore 

 formation occurs when the nutritive substances in the fluid are exhausted. 



Although t lie cycle of forms passed through in the lite-history of a liacterium 





f'n.. -'.'.4. / 



a, <l, Motile cells and 



chain of cells; /;, non-motile cells and chains of 

 cells: ., -spores from the zoogloea, >. (From A. 

 FISCHKK. r.j/7. ii lii i- \\dct er'n- ii. n-il, x 1500; <, 

 X 250.) 



