THE IRON-BACTERIA 



38* 



sheath will contain several hundreds of these bodies. Then 

 not only do the latter emerge from the apex, but they also 

 break through the sides. Many even elongate into new 

 threads from inside the sheath. In this condition the sheath 

 is covered with a fine tangled mass of projecting filaments as 

 shown in fig. 4,D. On these occasions we may presume also 



004,00 



0\OO 



1 o 



77? 



Fig. 4. — Crenothrix polyspora.', A-D, x 1,000; £, x 2,000. 



A, Mature thread open at the top. B, Young thread. C, Thread with rod-cells in process of liberation. 

 D, Appearance of thread during period of very rapid multiplication. It is filled with cocci, which in 

 germinating push out laterally through the sheath. E, Young thread stained to show transverse 

 walls of the sheath, s, sheath ; n, rod-cells ; m, cocci ; t, transverse walls of sheath. 



that the rate of growth of each filament is considerably quick- 

 ened, so that it is small wonder that there is such a phenomenal 

 increase in their numbers, and that they are able to impress 

 their colour on the water in which they thrive. Garrett 

 calls attention to the fact that in young threads the sheath 

 is in realit}^ a tube divided up into compartments each con- 

 taining a single cell. The writer has some unpublished notes 



