67 
Some diseased cabbage worms were received October 4 from Prof. C. P. Gillette, 
Ames, I«»wa. From one of these larva- a pure culture of the PieiHe rapce micrococcus 
was obtained. In this condition it was kept in a healthy growing state during the 
winter by frequent transfers to fresh media. In this manner the germ had been 
transferred eleven times, nine times on agar-agar and the la>t two in beef broth. 
The eleventh cultnre was used in the experiments August 20, alter having had about 
ten months of artificial cultivation. The culture was two days old when used in 
experiment 4. 
Experiment 4. 
A itf/Hst 20. — The culture liquid just spoken of was applied as follows : Two small 
bolls with involucres were well drenched in the liquid and two half-grown Heliothis 
larvae were placed on them. The larvae began sipping of the liquid, which insured 
their infection if possible. A small round cavity had been cut into the bolls and filled 
with the cultnre liquid. The worms decided to enter the bolls at these injured 
points, again exposing themselves to infection. Both continued healthy and hvK 
freely, bo much so that one fell a victim to the other through cannibalism. The 
survivor continued healthy to the last, pupated, and batched later as a robust, active 
moth. 
In isolating the cabbage-worm micrococcus from the diseased larva:' received from 
Profs. Osborn and Gillette, two other germs were isolated. On agar media the one 
produces a yellow growth, the other a beautiful pink one. In all the pre\ ions and 
subsequent studies the germ producing the pink growth was almost constantly ob- 
tained from diseased cabbage worms. It a\;is therefore thought advisable to give it 
a trial upon the Boll Worm. A broth culture was made and allowed to grow for 
two days, when it was applied as detailed in experiment 5. The germ had been 
carried over winter by artificial cultivations for a period of eight months and was t be 
tenth pure culture. 
On agar-agar the growth may be described as follows : At first small elevated round 
colonies having a translucent whitish appearance. These gradually spread and fuse, 
forming a continuous white growth. If it continues growing from the margins. 
these may be finely fringed, slightly branching or corrugated. As the growth be- 
comes thick, the surface becomes very much wrinkled or ridged. At this stage, and 
often earlier, i lie growth begins t inning to a pinkish color, finally becoming dial iiutly 
pink. The pink color appears in smooth growths or isolated colonies, as well. 
seemingly, developing as the germ ceases its most vigorous growth. The wrinkled 
scum seems rather to be evidence of a vigorous culture and the result of a s. i\ pro 
fuse growth. 
Experiment 5. 
August 15. — The husks of an ear of coin were torn away just enough to expose the 
silks and grains of corn. The culture liquid was then poured on the tip of the ear 
and allowed to soak in through t lie silks and run down t he length of t lie ear. One 
large Boll Worm and one half grown were in the ear. The liquid came into contact 
with both, and each was seen to sip of it. The following day the Larvae had eaten 
plentifully of the corn, including most of the grains w liieh bad been drenched w ith 
the charged liquid. Both larva' continued to feed, the larger one pupating and 
hatching later. The smaller one led for a time longer, during which no Unfavorable 
symptoms appeared, bu1 finally made good its escape from the pot while searching 
for a more desirable place to pupate. 
The disease ol Pieris rapce is found occasionally in most portions of 
Louisiana, but it is not of a virulent form in most cases, not causing 
deatb until the pupal stage is reached. June8 two dead pupae of this 
species were found upon cabbage plants in the field, A careful study 
