. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 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
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 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 in every way, except for exposure to radium, treated like the irradiated ani- mal. The two worms were then fixed and stained at the same time and in the same manner. Individuals in three different stages of development were selected for treatment: (1) immature worms of approximately 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 AUolobophora is shown in the accompanying table by the death of ten out of twenty-four of the. Fig- 1-— Diagram of cell con- taining the radium and the cylindrical wire cage to hold the worm used in experiments on AUolobophora. Above, the ap- paratus in cross ssction; below, plan, o, Wire cage; b, radium; c, glass floor of cell; d, sealing- wax rim; c, aluminum roof of cell, so bent as to form a trough to receive the caged worm. Magnified two diameters. Number of Strength of TAB Hours on LE. Duration of life Fate. experiment. radium. radium after radium. Young Worms. 1 Weak 3i Ohrs. Dead 2 i( 51 3 " <
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Keywords: ., bookauthorha, bookcentury1900, bookdecade1900, booksubjectzoology
