93 



and very feebly alkaline. It is made up of small roundish zooglcese, short chains 

 of a dozen or more segments, and slender short ro<ls, single, in pairs, or fours. Some 

 of the rods are actively motile. 



Sixty-sixth day. 



(1) Check. — Slime strongly alkaline to neutral litmus. 



(2) Grape mgar. — Slime n(jt alkaline. Distinctly acid on neutral litnms paper. 



(3) Cane sugar. — No alkaline reaction. Slime distinctly acid on neutral litmus 

 paper. 



TWEN'TV-THKKE I'KR (KNT .Sl'dAKS.^ 



These cultures were like the preceding- except that for each 10 c. c. 

 of ag'cir 3 grains of the specified sugar was used. The check tubes 

 had been slanted longer than the others and their surface was drier. 

 All were smeared with Ps. Ivyacinthi from an agar culture 24 daj's old 

 in the same way and with approximate!}^ the same amount of material. 

 The alkaline fruit-sugar agars already described were inoculated at the 

 same time and from this same culture, which was the check tube 

 described under the 17 per cent sugar agars. 



Seventh, day. 



(1) Chech. — A thin distinctly yellow growth over nearly the whole slant. 



(2) Grape sugar {3 grams Merck's c. p. anhydrous) . — No growth. 



(3) Cane sugar {3 grams white comrnercial) . — A very feeble, scrappy growth, not 

 forming a streak, but confined to the immediate vicinity of some small fragments of 

 slime, which were left unspread when the agar was inoculated. Not more than two 

 or three times as much slime present as was put into the tube in making the inocu- 

 lation. Twenty-three per cent cane-sugar agar strongly retards growth. 



Twelfth day. 



(1) Clieck. — Fully twice as much growth as on the cane-sugar agar. 



(2) Grape sugar. — No growth, although the surface of the entire slant was rubbed 

 with a mass of yellow slime as large as a pin head. 



(3) Cane sugar. — A distinct, rather thin, wet, yellow, rough-surfaced growth, which 

 covers about one-half of the slant (lower half). 



Thirtieth day. 



(1) (Jhcrk. — Surface of the streak smooth, wet-shining, and distinctly yellow; no 

 reticulations or shagreen. 



(2) Grape sugar. — \o growth. V'.s. hi/acliilhi \v\\\ not grow on 23 per cent grape- 

 sugar agar. 



(3) Cane sugar. — The lower three-fourths of the slant is covered with a distinctly 

 yellow growth, which is rather dry, Init looks wet under the hand lens. The surface 

 is not smooth, but is reticulate, areolate, or shagreened, the portions between the 

 grooves being lighter yellow and very smooth. This areolation is sliown in Bulletin 

 26 of this Division, in text fig. 3, which was made from this culture on the thirty- 

 third day. Theagarhas not dried out much, but the slime shows no tendency to flow. 



' The expressions 9,17 and 23 per cent are used for convenience. Of course, the 

 writer is aware that 3 grams added to 10 c. c. does not make exactly 23 per cent. 



