EXPERIMENT STATION BULLETINS. 229 



Potato tube-cultures.— A moist grayish white growth appears which dries down into 

 a mealy mass. 



Growth. — Rapid. 



Pigment. — None. 



Oxygen conditions. — It will grow without the presence of free oxygen, but the 

 growth is somewhat restrained. 



Odor. — A disagreeble odor. 



Acids.— No acids produced in any of the cultures, even in the presence of loctose 

 or glucose. 



Behavior to gelatin. — Liquefies. 



No. 117. 



Source. — Taken from changed Pasteurized milk L. 



Form and grouping. — Bacillus. Its length varies from 1 m to If m, and its length 

 from 3 m to 9 m. It is found single and in threads of different lengths. The ends are 

 round. 



Spores. — Median spores are developed. 



Protoplasm. — The protoplasm is granular. 



Motion. — It has a progressive serpentine motion. 



Staining reaction. — Ordinary aniline stains react readily. 



Tempzrature.— Its optimum temperature is 25° C.-30° C. It is not killed at 80° C. 

 for 20 min., but is killed at 85° for the same time. Develops very slowly below 16° C. 



Colonies. — The body of the colony is light brown and the border is irregular. From 

 the border radiate fine filaments which form a dense net work about the colony. 



Gelatin tube-cultures. — The growth is along the entire line of inoculation; the 

 growth is as heavy at the bottom as at the top. In liquefying the funnel formed has 

 straight sides and' reaches nearly to the bottom of the tube. The gelatin is gradually 

 1 quefied. 



Agar inclined tube-cultures. — A heavy, moist and wrinkled growth spreads over the 

 surface of the agar, the border of which is serrated. 



Bouillon cultures — A greasy thin growth forms on the surface. The cloudiness is 

 ev mly distributed and some sediment may be found at the bottom. 



Milk cultures. — The niiik is first loppered, then peptonized. 



Potato tube-culture. — 



Blood serum-cuZitwe.— Serum is completely peptonized. 



Growth . — Rapid . 



Pigment. — None. 



Oxygen conditions. — Grows anaerobically as well as aerobically. 



Odor.— 



Acids. — Acid is produced in the presence of lactose. 



Behavior to gelatin. — Liquefies. 



After reviewing the histories and bearing in mind the appearances of 

 these bacteria, it seems possible that numbers 30, 32, 43, 45, 46 might be a 

 single species, notwithstanding marked differential features when grow- 

 ing side by side under the same conditions. This too may be said of 107, 

 112, and 115; also of 116 and 117. This may be true of other combinations. 

 This, however, is a study by itself and months of work may not reveal 

 any satisfactory results, if we are to judge from the time and work put 

 upon the differentation of Eberth's bacillus and the Colon bacillus or 

 bacilli. Although we are unable to make a satisfactory statement in 

 regard to species, we hope that this phase of the work will not detract 

 from the value of the remainder. 



2. Determining the Source of Such Bacteria. 



No exhaustive work has been pursued in this connection. Our mir- 

 pose was simply to ascertain where these resistant bacteria may have 

 their source or where they may be found before reaching the milk. 



