42 BAGTEBIOLOGY. 



division in the other direction will now result in the 

 formation of a group of forms as tetrads. 



In the formation of staphylococci such division occurs 

 irregularly in all directions, resulting in the production 

 of the clusters in which these organisms are commonly 

 seen. (See Fig. 1, a.) With the streptococci, however, 

 the tendency is for the segmentation to continue in one 

 direction only, resulting in the production of long chains 

 of 4, 8, and 12 individuals. (See Fig. 1, h.) 



The sarcinse divide more or less regularly in three 

 directions of space; but instead of becoming separated 

 the one from the other as single cells, the tendency is 

 for the segmentation to be incomplete, the cells remain- 

 ing together in masses. The indentations upon these 

 masses or cubes, which indicate the point of incomplete 

 fission, give to these bundles of cells the appearance 

 commonly ascribed to them — that of a bale of cotton 

 or a packet of rags. (See Fig. 1, e.) 



The multiplication of bacilli is in the main similar to 

 that given for the micrococci. A dividing cell will elon- 

 gate slightly in the direction of its long axis; an inden- 

 tation will appear about midway between its poles, and 

 will become deeper and deeper until eventually two 

 daughter cells will be formed. This process may occur 

 in such a way that the two young bacilli will adhere 

 together by their adjacent ends in much the same way 

 that sausages are seen to be held together in strings 

 (Fig. 2,/), or the segmentation may take place more 

 at right angles to the long axis, so that the proximal 

 ends of the young cells are flattened, while the distal 

 extremities may be rounded or slightly pointed (Fig. 

 2, e). The segmentation of the anthrax bacillus, Nvith 

 which we are to become acquainted later, results, when 



