158 C.-E. A. WINSLOW AND ANNE F. ROGERS 



therefore of significance. It is questionable, however, whether it is 

 one of the most important characters in this group of bacteria. It 

 appears from the published descriptions of species that this property 

 is not correlated with any other character, arising independently in 

 forms exactly resembling non-motile forms in every other respect. 

 On account of its rarity and this apparent lack of correlation with 

 other differences, as well as on account of the difficulty of studying it, 

 the property of motility has been so far omitted from the present study. 



Spores. The experiments carried out by Ellis (1902) strongly 

 suggest the presence of specially resistant cells in old cultures of 

 the cocci. His figures are, however, by no means conclusive as 

 to the existence of true spores. In the absence of any observations 

 as to germination, we have not felt that the evidence warranted 

 extensive microscopic study of this character. 



Fission. A study of the conditions influencing the growth- 

 forms of the Coccaceae should be of considerable interest. Pairs 

 and chains are apparently associated with meager, and groups and 

 packets with more abundant, development. The effect of the gen- 

 eral rate of growth must, however, be modified by the rate at which 

 cell-wall and cell-protoplasm, respectively, are formed. 



A careful study of the method by which these groupings arise 

 in cell-division, such as could be made by the use of Hill's hanging- 

 block method, would no doubt throw much light on all such points, 

 and should precede any final conclusions as to the relationships of 

 the cocci. In examining a large number of organisms, however, 

 the agar block would have proved too time-consuming. We have 

 therefore limited ourselves to the observations made on stained 

 preparations from ordinary cultures. 



Capsules. Considerable preliminary work failed to indicate any 

 constant differences in capsule formation among the cocci studied. 

 This character appears to be of considerable value among the 

 diplococci (Buerger, 1904); but even with them it varies markedly 

 with the medium used for cultivation. We cultivated certain select- 

 ed organisms in broth at 20 and at 37, on nutrient gelatin, acid 

 gelatin, alkaline gelatin, anaerobic gelatin, and Nahrstoff-Heyden 

 agar, and examined them at intervals by Welch's staining method. 

 In every case capsules were apparent at some stages, being most 



