BACTERIOLOGICAL INTRODUCTION 13 



group are represented in Figs. 1 and 2. The cells are 

 small, circular, and fairly regular in size in each 

 specimen. The method of preparation prevents any 

 conclusion as to the genetic relations of the groups. 

 In Fig. 46, which represents the Staphylococcus 

 Pyogenes Aureus in pus, the natural grouping of the 

 organisms is better seen. 



(b) Diplococci. — These are formed by the uniaxial 

 division of the spherical cell and the coherence of 

 the two resulting cells. On the further division of 

 these cells the cohesion between the original pair 

 apparently breaks down, so that successive pairs 

 are formed. Fig. 3 shows diplococci occurring in 

 sputum. The individual cells in this instance are 

 somewhat elongated, and with a lens various stages 

 of division may be observed, some of the longer cells 

 being in a state of incipient sub-division. This 

 lengthening of the cells which precedes division gives 

 a bacillary form to the organisms. In some cases 

 — e.g., the gonococcus, Fig. 49, the division is not 

 accompanied by elongation, so that the resulting 

 diplococcus presents two flat opposed faces. 



(c) Streptococci (Fig. 4).— These are organisms 

 occurring in chains of varying length formed by 

 successive uniaxial division of the spherical cell, the 

 successive planes being parallel to one another, and 



