362 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
which was coated with a delicate film of paraffin. This sheet was 
bent so as to form a longitudinal trough, 
in which the animal was laid surrounded 
by a piece of paraffined brass netting 
bent into the form of a tube. Wet filter 
paper was laid over the netting to keep 
the worm moist. The occasional change 
of position on the part of the worms 
during treatment and the production of 
secondary radiations from the netting 
above them both contributed to still 
greater uniformity of exposure. The 
gamma rays were so weak as to be negli- 
gible. For each experiment two _ indi- 
viduals of equal size were selected, one 
for exposure to radium, the other for the 
control experiment. The one not irradi- 
ated was placed over an empty cell and 
aint tie saint ats n every way, except for exposure to 
cylindrical wire cage to hold the radium, treated like the irradiated ani- 
worm used in experiments on mal. The two worms were then fixed 
Allolobophora. Above, the ap- : : i 
paratus in cross section: below, 220 stained at the same time and in the 
plan. a, Wire cage; b, radium; Same Manner. 
c, glass floor of cell; d, sealing- Individuals in three different stages of 
wax rim; e, aluminum roof of d l t lected for t t t: 
cell, so bent as to form a trough pies 1s eae Mabaso pie: pare 
to receive the caged worm. (1) immature worms of approximately 
Magnified two diameters. one tenth the bulk of the smaller adults; 
(2) adults of rather small size, found to 
have a well developed clitellum and reproductive organs; (3) large’ 
worms with reproductive organs active, taken while copulating. 
That radium has an effect upon Allolobophora is shown in the 
accompanying table by the death of ten out of twenty-four of the 
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TABLE. 
Number of Strength of Hours on Duration of life Fate. 
experiment. radium. radium after radium. 
Youna Worms. 
1 Weak 33 0 hrs. Dead 
? a9 5} 3 ce ins 
3 i 13 45 days Killed 
4 3 64 a kt “c 
“4 
