20 The Colorado Experiment Station 
28° C., abundant growth on agar and moderate in broth after 
4 8 hours. 
20° C., moderate growth on agar and slight in broth after 
48 hours. 
10° C., slight growth on agar and none in broth in 48 hours. 
6.5° C., slight growth on agar and none in broth in 48 hours; 
moderate growth on agar and slight in broth in 6 days. 
10. Relation to Oxygen. 
Ps. medicaginis, n. sp. appears to be an obligative aerobe. Stab 
cultures were made in glucose litmus gelatin and placed in an 
atmosphere of hydrogen in a Novy jar. No growth whatever 
took place in 120 days. Again, in our studies upon gas produc¬ 
tion from the different sugars, glycerine and mannite, we have 
observed that no growth occurred in the closed arm of the 
fermentation tubes and that there was a sharp line of demarca¬ 
tion between the growth in the open arm and the clear liquid 
in the closed arm. This would seem to point strongly toward 
the aerobic nature of the germ. The total absence of any deep 
growth in the gelatin stab serves to emphasize further this 
feature. 
11. Effect of Dessication. 
The organism is relatively resistant to drying, being able to 
withstand dessication for eleven days when spread on cover 
glasses and dried in sterile Petri dishes. A suspension of the 2 4 
hour growth on agar was made in sterile water, and one loopful 
of this was spread over each of a number of one-half cover 
glasses, sterilized by flaming. These smears were placed in 
sterile Petri dishes at once and allowed to dry. Every twenty- 
four hours for a period of twenty-two days, two of these in¬ 
oculated cover glasses were taken out and dropped into tubes 
of sterile broth; if growth resulted, this was taken as evidence 
that the germs had not been killed by drying. Detailed obser¬ 
vations are given in Table No. 5 below. 
table no. 5—effect of dessication. 
Number of Days 
Dried 
Growth Resulting- in Broth After Given Number of Days 
1 d. 
2 d. 
3 d. 
4 d. 
5 d. 
6 d. 
7 d. 
8 d. 
9 d. 
10 d. 
1. 
0 
0 
4 
4 
4 
4- 
+ 
4- 
4 
4- 
2. 
0 
0 
+ 
4- 
4 
4- 
4- 
+ 
4- 
+ 
3. 
0 
0 
4 
+ 
4- 
4- 
4 
+ 
4- 
4- 
4. 
0 
0 
4* 
4- 
+ 
4- 
4- 
4- 
4- 
4- 
5 . 
0 
0 
0 
0 
4" 
4 
T 
4 
4 
4 
6 . 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
7. 
0 
0 
+ 
+ 
4- 
4 
4- 
4- 
4- 
4 
8 .. 
0 
0 
0 
4 
4" 
4- 
4 
4- 
4- 
4 
9 . 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
10. 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
11. 
0 
0 
0 
0 
0 
0 
0 
4 
4- 
4 
12. 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
13 . 
0 
0 
0 
0 
0 
0 
•0 
■ 0 
0 
0 
14. 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
15. 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
16. 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
17. 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
18 . 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
19 . 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
20. 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
21. 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
22. 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0. 
0 
0 
+ 
4- 
4- 
+ 
4- 
+ 
4 
4 
