356 



THE IRON BACTERIA. 



multiply rapidly, the upper members are forced out of the sheath, 

 but are, for the most part, already subdivided by the development 



of partition walls 



ate oJiu>. in all three direc- 



tions of space 

 into small rounded 

 cells, which there- 

 upon make their 

 escape. The new 

 cells vary in size 

 according to the 

 rapidity of this 

 process of subdivi- 

 sion, and are cor- 

 respondingly dis- 

 tinguished byZopf 

 as micrococci (r), 

 and macrococci (q) 



proposed the terms 

 microgonidia and 

 macrogonidia, be- 



UY QNA O K/y N cause their method 



\\ vl ft HJHr H of formation bears 

 \ VA B HH4 U A a slight apparent 



resemblance to the 

 endospores (known 

 as gonidia) of cer- 

 tain Eumycetes, 

 with which we 

 shall become ac- 

 quainted in the 

 second volume. 

 The dimensions of 

 these cocci vary 

 between i /x and 

 6 /x. Their cell- 

 walls swell up 

 readily, and unite 

 toformzoogloea(/) 

 up to i c.m. in 

 diameter. Under 

 favourable condi- 

 tions the cocci 

 then grow, by re- 

 peated subdivision 



and sheath-formation, into the thread forms already described. 



ZOPF (VI.) observed that in many cases this occurs before they 



FlQ. 65. Crenothrix polyspora. 



i-r. thread-forms of different diameter. 



n-q. macrococci, and r, micrococci splitting off. Magn. 



about 600. 

 a-e. reproduction of the cocci ; /. colony (zooglcea) of cocci ; 



g. same, natural size ; h. same beginning to germinate. 



Magn. 600. (After Zopf.) 



