324 IMPORTANT VARIETIES OF FISSION-FUNGI. 



united in threads. It readily forms roundish to oval 

 spores (42, xi). 



Motility. — It propels itself by means of numerous peri- 

 trichous flagella (42, xn). 



Staining Properties. — Stains by Gram's method. 



Requirements as to Nutrient Media, Oxygen, etc. 

 — The same as Bac. subtilis j grows rapidly. 



Gelatin Plate. — (a) Natural size: After one or two 

 days the colonies sink into the gelatin, grayish-white, deli- 

 cate, wrinkled films being formed, which, even later, after 

 liquefaction of the entire plate, do not disintegrate (42, 

 VII ). 



(b) Magnified fifty times: In the early stage the colonies, 

 especially at the periphery, resemble the smallest typhoid 

 colonies until they begin to sink into the gelatin. (Com- 

 pare also 43, xi.) Soon this transparent zone changes 

 into a crummy mass, which is coarsely granular internally 

 and possesses lobular markings, while the peripheral por- 

 tion presents lobules separating from each other. Finally 

 the entire colony acquires the appearance of a distinctly 

 moruloid, brown, loosely attached heap, resembling a 

 panther skin (42, vm and ix). Besides the forms just 

 described, there are often forms furnishing a transition to 

 those of the Bac. mesentericus. 



Gelatin Stab. — Upon the surface, a grayish- white, rag- 

 ged-edged growth with a fatty luster. Gradually from this 

 there is developed a dense film, which sinks into the gelatin 

 in the form of a cup. The liquefied zone is cloudy with 

 a dirty grayish-white precipitate (42, i). 



Agar Plate. — (a) Natural size. Surface growth : White 

 to whitish-gray, moistly shining, even-bordered or slightly 

 granular, a little elevated. Deep : Roundish to whetstone- 

 shaped, white. Sometimes in older cultures there occur 

 folded or rounded elevations (42, iv). 



(6) Magnified fifty times. Superficial: Roundish, gray, 

 homogeneous colonies, without markings, becoming 

 opaque toward the center, transparent at the periphery, 

 and beset by long, often tortuous, plaited hairs (42, vi). 

 Deep : Roundish to whetstone-shaped, gray, homogeneous, 

 opaque, sometimes also with a limited development of 

 hairs (42, v). 



