390 W. CECIL BOSANUUET. 



(figs. 12, 13). This alternative possibility was strongly 

 brought to iny iniud by a preparation in which many living 

 spirochastes appeared to have loops at one extremity, while 

 they revolved rapidly on a longitudinal axis. As their move- 

 ments slackened, these organisms appeared to have a shape 

 which might bo compared with that of a hair-pin having its 

 " legs" twisted together. On fixing and staining this pre- 

 paration, specimens were found both of the condition just 

 described (fig. 14), and also oF wh;it seemed to be a succeed- 

 ing stage, in which division had taken place at the bend of 

 the loop (fio'. 15). I could find no instance of a spirochtete 

 simply looped at one extremity, as might have been expected 

 to occur if longitudinal division took place, starting at a 

 point a little distant from the extremity of the spirochgete. 

 1 was at first tempted to regard the pairs of closely apposed 

 organisms here seen as being instances of conjugation, but 

 the explanation just given seems more probable in view of 

 the looped forms seen alive in the preparation. Division by 

 '^ incurvation " is stated by Gross to occur in the spirochgete 

 present in Pecten jacobseus (called by him Cristispira 

 pectinis), and he believes it to be the characteristic of all 

 spirochastes. Nuttall, Fantham and Porter state that in the 

 small spirochtctes both transverse and longitudinal division 

 occurs. If this be so, it would be interesting to ascertain 

 whether any difference in environment is responsible for 

 their adoption of each method respectively, or whether the 

 two processes occur at different points in the life-cycle. 



With regard to the internal structure of Sp. anodontie, 

 I have always found that specimens taken from the crystal- 

 line style of the mussel stain homogeneously like Bacteria 

 (fig. 7). Those, however, which are present in the stonuich 

 of the mollusc, especially after the style has dissolved, show 

 beading of the substance of the organism, as is depicted by 

 Keysselitz in his original memoir (figs. 16, 17, 18). Since 

 the style is apparently the most favourable medium for the 

 life of the spirocha^te, I am inclined to look upon the beaded 

 forms as either iuvolutiounry or developmental. The fol- 



