20 BACTERIOLOGY. 



granular disintegration of the cell-contents 



(Fig. 10). 



If the outer cell-membrane swells up and 



becomes gelatinous, an envelope or capsule is 



formed. The gelatinous scum or zooglcea that 



spreads over the sur- 

 face of decomposing 

 fluids is composed of 

 ^ .. such a film of bac- 



teria held together 

 by their gelatinous 

 envelopes. Ins i d e 



the mass an order- 

 Fig. 10. Granular disintegration of ^ ., 



bacteria, 4v.supposed typica dis- ly arrangement of 



integration of a spirochiete from 11 



swamp -water, first into longer, Cell groups may CX- 



then into shorter, rods, and finally . t T\ 11 1 



into little spheres (after Zopf). B, ISt. Pellicles may 



ordinary breaking up into seg- i r i , 1 



ments, and C, granular disinte- be tormed OU the 



gration of comma bacilli (after < r n i i 



Hueppe). surface or fluid and 



solid media, and 



these may be thin or thick, smooth or corru- 

 gated ; in the interior of fluids the growth may 

 be globular, ramifying or in grape-like clus- 

 ters. The zooglcese or colonies upon certain 

 solid nutrient media like gelatin, agar-agar 

 and potato are especially characteristic (Fig. 

 n). The shape of the colony and the kind of 

 development vary according to the chemical and 

 physical conditions that affect nutrition but 

 under similar conditions are always approxi- 



