81 



(2) The second test was be<>'iin June U'> and closed Jul}^ 1. Four 

 media were used, viz, +15 peptonized beef broth (stock 473a), peptone 

 water with addition of grape sugar and methylene blue (stock 489), 

 peptone water with sodium chloride and rosolic acid (stock 498), and 

 Uschinsky's solution (stock 496). Various organisms were tested. 

 Each tul)e received an ecpial ([uantity of tlie culture fluid, i. e., one 2mm. 

 loo}) of cloudy ])roth from cultures five days old. The media used had 

 already l)een tested and the various organisms were known to grow 

 well in it. 1'he inoculations were all made from media in which the 

 various organisms grew well, viz, peptonized beef broth neutral to 

 phenolplithalein (stock 5.15e). The general management of the experi- 

 ment in other particulars was the same as in the preceding. 



The seal was broken, as before, on the sixteenth day (July 1), and the 

 results were as follows: 



Ps. hyadnthi: 



(a) Beef broth. — July 1, no growth. July 2, clear. July 5, clear. July 9, clear. 

 July 16, feebly clouded; good rolling clouds on shaking; a great retardation of 

 growth. 



(b) Grape siujar peptone ivaler ivith methylene blue. — July 1, no growth; on removal 

 the fluid was nearly colorless, but the surface layer in contact with the air immedi- 

 ately became greenish blue and in a few minutes the whole fluid was oxidized to this 

 color; this result also shows that the jar remained free from oxygen. July 2, clear, 

 July 5, clear; July 9, clear; no visible growth. July 16, well clouded; color wholly 

 reduced, except in a thin layer at the top next to the air; this growth and reduction 

 of color began about July 12, on shaking, the color comes back, but is again reduced 

 on standing for a few minutes; marked retardation of growth. 



(c) Salted peptone water witJt rosolic acid. — July 1, no growth; color of the fluid 

 the same as in the uninoculated tubes. July 2, clear. July 5, no growth. July 9, 

 clear. July 16, no growth visible; no change of color. 



Ps. campestrii>: 



(a) Beef broth. — Lost by breaking. 



(b) Grape sugar j)eptone water witli methylene blue. — July 1, no growth; fluid nearly 

 colorless when taken from the jar; on contact with the air it began to color at once and 

 in a few minutes was greenish blue. July 2, clear. July 5, clear. July 9, clear. 

 July 16, fluid greenish blue; no growth. 



(c) Salted jjeptone teater nilh rosolic acid. — July 1, no growth; the fluid is the same 

 color as when inoculated. July 2, clear. July 5, no growth. July 9, clear. July 

 16, clear; no change in color. 



Ps. stewarti: 



(a) Beef broth. — July 1, no growth. July 2 (temperature 28° C), very feebly 

 clouded. July 5, moderate clouding, most in the upper 6 nnn. where there are numer- 

 ous small zoogloese wl ;ch stream down on gentle shaking; much increase in growth 

 since July 2, but no rim or iiellicle; July 9, moderately cloudy; no rim, but a delicate 

 pseudo-pellicle of separate zoogkcfc. July 16, feebly clouded.; a moderate amount 

 of yellow precipitate and a thin fragile yellow iridescent pellicle, which breaks up 

 on slight shaking into a great many roundish zoogloejc; growth in the air not dis- 

 tinctly retarded. 



(b) Grape siifjar peptone water vnthmetliyleuc blue. — July 1, clear. There seems to 

 have been a little growth — i. e., there are a few tiny floating flecks of uncertain 

 nature, there is a small amount of colorless precipitate which is wanting in the cor- 



21788— No. 28—01 6 



