H. B. Hutchinson and J. Clayton 17:J 



group, (6) mucilage which does not give rise to optically active com- 

 pounds on hydrolysis and (c) small quantities of volatile acids. 



9. Evidence is also adduced to show the relation of cellulose de- 

 composition to the assimilation of atmospheric nitrogen. 



DESCRIPTION OF ILLUSTRATIONS ON PLATES I-III. 



(Photomicrographs — raagnification 1000 diameters.) 

 Platk I. 



Fig. I. Test tube cultures with mineral salt solution and filter paper; 4, 7, and 12 days 

 old. 



Fig. 2. Petri dish culture on sodium nitrate-mineral salt agar with filter paper super- 

 imposed. Showing holes in paper by the growth of 5. cytojihaga (nat. size). 



Fig. 3. Photomicrograph of young culture of S. Ci/tojjAaja in filter paper tube. Showing 

 typical incurvation of thread form. 



Fig. 4. Photomicrograph of J'omig culture of .S'. cylophaija in h<|uid culture with jjre- 

 cipitated cellulose. Showing well-marked sinuous forms. 



Fig. 5. Photomicrograph of i\ cytophaga in mo.S6' culture on nutrient agar. Enfeebled 

 forms exhibiting initial granulation of cells. 



Fig. 6. Photomicrograph of yoimg culture showing equatorial or polar segregation of 

 chromatin substance. "Deposition" stain with alcoholic fuchsin. 



Plate II. 



Fig. 1. Photomicrograph of culture on oat plant residue showing cells with chromatin 

 "bridge" (below centre) and also sporoids. 



Fig. 2. Photomicrograph of culture on filter paper, incubated at 35°. All stages from 

 the thread to the final sporoid are represented. 



Fig. 3. Photomicrograph of same culture at a later stage, showing formation of a 

 prc-sporoid stage with double granules (or band). 



Fig. 4. Photomicrograph of culture sliowing (below centre) cells witli (n) band, 

 (6) bridge, and (c) double granules of chromatin. Also adjacent cell with internal coccoid 

 structure. 



Fig. 5. Photomicrograph of sporoids of different ages and, below, several ai)pareutly 

 devoid of chromatin substance. 



Fig. 6. Photomicrograph of older culture showing predominance of sporoids. 



Plate III. 



Fig. 1. Final stage in the dissolution of a cellulose fibre. 



Figs. 2, 3, and 4. Photomicrographs showing emergence of thread form from the 

 sporoid. Preparation for Fig. 3 stained with alcoholic fuchsin. 



Fig. 5. Photomicrograph of Indian ink preparation with sporoid and thread form. 



Fig. 6. Photomicrograph of culture shoivn on Plate II, figs. 2 and 3, second genera 

 tion after transference from 35° to 25°. Showing intense granulation of cells. 



{Received November 30tk, 1918.) 



