294 IMPORTANT VARIETIES OF FISSION-FUNGI. 



shining, sometimes presenting very beautifully a combina- 

 tion of small boughs (29, i). 



Agar Plate. — (a) Natural size: After twenty-four hours 

 the colonies are 2 to 4 mm. wide, grayish-white, with deli- 

 cately fringed border, and are surrounded by a thin trans- 

 parent zone (30, iv). In a short time the whole plate is 

 covered with a gray veil. 



(b) Magnified fifty times : After twelve hours the colonies 

 are like exceedingly delicate balls of hairs, and visible 

 only with a very narrow opening in the diaphragm (30, 

 v). Later the colonies take on a more intense yellowish 

 color, the branching increases, and the extension takes place 

 rapidly but irregularly. The colony can not be distin- 

 guished from a deep subtilis colony (30, in). After a few 

 days the colony has become yellowish -brown, and is 

 exceedingly matted and tangled. When magnified 90 

 times, it is seen that the delicate veils about the superficial 

 colonies consist of thin layers of bacteria (30, vi). 



Agar Stab. — Similar to that in gelatin (29, in). 



Agar Streak. — Exceedingly delicate, grayish-white, 

 transparent, shining. In the middle there sometimes is a 

 paler streak. In a short time the entire surface is over- 

 grown ; hairs are not usually distinguishable ; the water 

 of condensation remains clear, with a whitish precipitate. 



Bouillon Culture. — Clear or slightly turbid, with a 

 little sediment. 



Milk. — Not coagulated, amphoteric reaction. 



Potato Culture. — Slight, yellowish-gray growth. 



Chemical Activities. — Produces typical putrefaction 

 with pronounced foul odor upon nutrient media rich in 

 albumin. It is remarkable that Kuhn (A. H. xiii, 40) 

 could never demonstrate indol production in our institute, 

 while we now find some indol. 



Distribution. — (a) Outside the body : Isolated by Kurt 

 from hen dejecta ; by Kuhn, repeatedly from putrefying 

 mixtures, (b) Inside the body it has never been found. 



Related Varieties. — The Bact. vulgare, forma Zenkeri, 

 which has so far been but little studied, is most closely 

 related. The principal difference lies in the beautiful little 

 hairs, bristles, and threads sent out from the stab culture. 

 According to Hauser's description, it appears that also the 



