432 C. CLIFFORD DOB ELL. 



form, dispoi-ic habit, and cliromidial nucleus cliaracteristic of 

 other flexilis forms, has also stages in its life-cycle during 

 which the chromatin is arranged in a series of large nucleus- 

 like masses. The significance of this arrangement has not 

 been determined. 



(b) The form from Lacerta muralis. — I obtained this* 

 organism in a single lizard whicii I caught near Naples 

 (Pozzuoli). As in the case of the preceding organism, I have 

 been able to make only very fragmentary observations upon 

 it. Unfortunately, I examined it only casually in the living- 

 state — believing it to be the ordinary flexilis form described 

 above (p. 428). When alive it showed active movements and 

 Avas flexible — like the ordinary flexilis fornis from the lizard. 



To my great regret I made only a single preparation of this 

 organism — a dry smear on a coverslip, fixed in absolute 

 alcohol and stained by Giemsa's method. All my observations, 

 therefore, are based on this scanty and unsatisfactorily treated 

 material. 



It might be urged that the appearances presented by the 

 organisms in this preparation are due to imperfect fixation. 

 This may perhaps be true to some extent, but I do not think 

 it is altogether justified. In the first place, other organisms 

 in the same preparation (e.g. some spirogyra forms and 

 other bacilli) appear quite normal. In the second place, 

 drying and fixing in this manner never produces similar 

 appearances in the ordinary flexilis forms. 



Some of the oi'ganisms in this slide are shown in figs. 85-90 

 (PI. 17). Many of them are of the form seen in fig. 89 — that 

 is to say, they present the appearance of long, slender 

 Bacteria of the flexilis type. Tliey possess a nucleus of the 

 chromidial type — many of the chromatin granules being, liow- 

 evei", relatively very large. Large individuals reach rather 

 over 40 ju in length, though most of them are narrower than 

 the ordinary flexilis forms (cf. figs. 89 and 8o). 



I have found in addition to these characteristic flexilis 

 forms a number of individuals which display quite a different 

 kind of nuclear arrangement. The chromatin is in large. 



