80 



no growth. July 16, no growth; the agar is still quite moist, i. e., it has dried out 

 only a little; this tube and the two preceding were inoculated from the same 

 culture, tube 4, June 11 (stock 473a) , which was well clouded. 

 Ps. cavipestris: 

 {a) Potato. — June 30, no growth. July 2, no growth. July 5, no growth. July 9, 

 no growth. July 16, no growth; plenty of water in the bottom of the tube and the 

 aerial part of the potato moist; this tube and the two following were inoculated 

 June 14 with a large 2-mm. loop from tube 13, June 11 (a beef-broth culture inocu- 

 lated with a 2-mm. loop of yellow slime from a potato culture 36 days old); tube 

 13, June 11, clouded in 24 hours, and was well clouded in 48 hours. 



(b) Beef broth. — June 30, clear; no trace of growth. July 2, clear. July 5, lost by 

 accident. 



(c) Agar. — June 30, no growth. July 2, no growth. July 5, no growth. July 

 16, no growth; failure is not to be accounted for l)y any drying out of the agar. 



Ps. stevarti : 



(a) Potato. — June 30, no growth. July 2, no growth; plenty of water in the tube. 

 July 5, no visible growth. July 9, potato grayed, a very feeble buff-yellow growth, 

 not over one-fiftieth as much as in the corresponding tube of Ps. hyacinthi. July 17, 

 a feeble buff-yellow growth in the air; potato quite gray; fluid feebly browned; 

 very little precipitate; a marked retardation of growth; this culture and the two 

 following were inoculated from tube 22, June 11 (stock 473a), a well-clouded culture. 



(b) Beef broth. — June 30, clear; no growth, or a very slight one which has settled; 

 the nature of the slight precipitate is doubtful; it was not examined microscop- 

 ically; it is possible that a trace of oxygen was left in the medium, and this organism 

 seems to require less 0. for its growth than Ps. hyacinthi or Ps. campestris. July 2, 

 fluid feebly clouded; no rim or pellicle, but many small zoogloese. July 5, well 

 clouded. July 9, well clouded; no pellicle or rim. July 16, moderately cloudy, no 

 rim or pellicle, but numerous small zoogloese and a moderate amount of yellow pre- 

 cipitate; no decided retardation of growth in the air. 



(c) Agar. — June 30, a distinct but very feeble growth; it is visible to the naked 

 eye in the V and on the slant, if the tube is held up to the light, but it is best seen 

 with a Zeiss X 6 aplanat; under this magnification there appear to be 300 or 400 

 tiny whitish colonies on the slant surface, and in the fluid a feeble clouding and 

 some tiny zoogloese; no yellow color is visible. July 2, a streak composed of 

 several hundred small white colonies barely visible to the naked eye. July 5, a pale 

 yellow growth now covers about 1 sq. cm. in the lower part of the streak. July 9, 

 some increase of the yellow growth, but not over one-third of the slant covered; 

 farther up there are more than 100 minute colonies, which can be seen only with a 

 lens. July 16, growth on the lower part of the. slant has doubled and is yellower 

 than it was (buff-yellow) ; the tiny colonies on the middle and upper part of the slant 

 have not increased any in size; they are dead; the agar has dried out but little. 



B. pyocyaneus-pericarditidis: 

 (a) Potato.— June 30, no visible growth. July 2, an abundant growth, whitish 

 with a tinge of yellow; no fluorescence. July 5, potato grayed throughout. July 9, a 

 thin dirty white (or brownish white) growth; no fluorescence; growth in the air 

 not retarded by the hydrogen. 

 B. aniylovortts: 

 (a) Potato. — June 30, no growth. July 2, fluid well clouded and a distinct white 

 growth on the potato out of the water. July 5, fluid heavily clouded; potato feebly 

 grayed; growth in the air not retarded. 

 B. coli: 

 (a) Potato. — June 30, fluid well clouded, doubtful as to growth out of the water; 

 if any, it is slight and of the same color as the potato; potato not grayed. July 2, 

 scanty wet-shining white growth on the potato out of the water; organism will 

 grow in hydrogen. 



