73 



striking. The tiny bacterial mass referred to contained no chains, no 

 spores, and no invohition forms. It consisted of slender rods, single 

 or in pairs and very short, as if not now dividing. Exposure of these 

 rods for 10 minutes to a temperature of 74'^ C. falling to 60° C. killed 

 all of them. 



The unexpected feature of this experiment was that after removal 

 to the air growth did not appear in these tubes as soon as it did in the 

 check tubes; in other words, the sojourn in the nitrogen seemed to have 

 exerted an injurious influence. One of the tubes (that inoculated from 

 the solid culture) showed a slight growth at the end of the third day, 

 the other one not until the fifth day. Five days after removal from 

 the nitrogen the bacteria in one tube had made al)out as much growth 

 as the check tubes made in 48 to 60 hours. In the other tube they 

 had made a thin pale yellow growth covering not more than 1 sq. 

 cm. — i. e., not more than one-tenth as much growth as the check tube 

 made in the same time. In the course of another 3 or 4 days the 

 bacteria in both tubes made an abundant bright yellow growth. 



Ps. Stewart i tested at the same time behaved in the same way. At 

 the end of 15 days, when the seal was broken, there was no 3^ellow 

 precipitate or visible slime, colored or colorless, in either tube. The 

 two check tubes showed a distinct growth in 48 hours, and continued 

 to grow in a typical wa}". On the contrary, there was no visible 

 grow^th in either tube on the fourth day after removal from the nitro- 

 gen. On the fifth day in the tube which was inoculated from a solid 

 culture there was a slight yellow growth over a few square millimeters. 

 In the other tube no growth was visiVjle until the eighth day after the 

 removal, and then it was scanty. This cylinder stood in one-half c.c. 

 water and was still moist. Two days later there was a good growth 

 on both cylinders. 



(2) The stock in the second experiment with Ps. hyaclnthi consisted 

 of 6 tubes of white turnip. Each of 3 was inoculated with one loop 

 of a ver}' cloudy beef-broth culture 6 days old. Each of the other 

 3 was inoculated with one loop of very cloud}' fluid from the bottom 

 of a young bright yellow and very vigorous culture on coconut 

 after prolonged shaking.. Two of the tubes were held as checks. The 

 other 4 were put into 2 U tubes in the way already described. In 

 each case a test tube (capacity 25 c. c.) packed nearly full of pN'rogallic 

 acid was then filled with 6i per cent caustic potash water and imme- 

 diately thrust into the other arm of the tube, which was then plunged 

 into the mercury. By the end of 24 hours, and prol)abl3^ sooner, the 

 absorption of the oxygen was complete — i. e., there was no farther 

 rise of the mercury or change in the color of the pyrogallic acid. 



Penult. — In one of the check tubes growth was plainly visible on the 

 third day, in the other not. On the sixth day in one check tube there 

 was an abundant smooth, wet-shining growth over the whole cylinder 



