18 



Uschixsky's Fluid. 



This fluid proved to be a very poor medium for the cultivation of 

 I^s. hyacintld. If only a few bacteria were put in. the fluid remained 

 clear. If more were put in, growth appeared, but clouding was retarded 

 (sometimes as long as 18 days) and was never other than feeble. On 

 standing several weeks, there formed a feeble rim. at first white, then 

 yellow, and a translucent pellicle dotted with roundish yellow zoogloe^e. 

 which became yellower. If the rim or pellicle was shaken down into 

 the bottom of the tube while it was still pale, it never acquired any 

 deeper yellow. The fluid was never more than feebly clouded. The 

 precipitate was bright yellow, but very scanty, amounting at the end 

 of a month to a breadth of only 2.5 mm. on the bottom of the tube. 

 At the end of '1 months seven-tenths of the original fluid remained. 

 It had cleared, was free from any brown stain, and contained no 

 crystals. 



Ver}' delicate white films and woolly flocculeut bodies formed In this 

 fluid and never became yellow. Under the microscope these colorless 

 shreds and fihns consisted of enormous numbers of short, slender, 

 motionless rods, so united that when the cover glass was jarred the 

 mass moved as a whole. At first these bodies were supposed to be 

 contaminations. The rods, however, were of the right size and shape 

 for Ps. hyaclntJiL and when these films and flecks were removed to beef 

 broth, potato, or other suitable media only this one yellow organism 

 developed. These bodies seemed so remarkable that a year later the 

 experiments in Uschinsky's solution were repeated, wiith, however, 

 identical results. Ps. campestris and Ps. phaseoli also grew feebly in 

 this solution and with retardation, but without the films characteristic 

 of Ps. hyacinthi On the contrary, Ps. steicarti grew in it for a long 

 time, and very copiously. Ps. hyacinthi grew very much better in 

 Uschinsky's solution when 1 per cent Witte's peptone was added to it. 

 In 3 weeks the growth in this peptonized fluid was 100 times as 

 abundant as in the check tubes. 



31iLK AXD Litmus ^Iilk. 



The milk was obtained from a clean dairy and its reaction was 

 amphoteric. It was used, nearly free from cream, in 10 c. c. por- 

 tions, in test tubes of resistant glass. It was sterilized (about 2-1 

 hours after milking) by subjecting it. in wire crates, to streaming 

 steam for 15 minutes at 100^ C. on each of 1 consecutive days, and 

 none of the many check tubes ever spoiled. 



Many tubes of milk were inoculated with Pt?. hyaciiithi at different 

 times. All gave the same result. For some time there is no visible 

 change other than the formation of a yellow bacterial rim or pellicle, 

 or both, with some yellow precipitate. Accompanying this growth 



