The reactions of Planarians to light . themirror into the black tunnel. Most of the light is absorbed in thetunnel, only an insignificant minimum being reflected back to theaquarium floor. Otherwise complications in the character andintensity of the light might arise. By moving the hood (B) up and down and by using lamps ofdifferent candle powers a variety of intensities was obtained. Thelamps used were tested by means of a Lummer-Brodhun pho-tometer, the loss by reflection from the surface of the water both atthe heat screen and at the aquarium being reckoned out in deter-mining the different
The reactions of Planarians to light . themirror into the black tunnel. Most of the light is absorbed in thetunnel, only an insignificant minimum being reflected back to theaquarium floor. Otherwise complications in the character andintensity of the light might arise. By moving the hood (B) up and down and by using lamps ofdifferent candle powers a variety of intensities was obtained. Thelamps used were tested by means of a Lummer-Brodhun pho-tometer, the loss by reflection from the surface of the water both atthe heat screen and at the aquarium being reckoned out in deter-mining the different intensities employed. By simple observation, data for such criteria of behavior as The Reactions of Planarians to Light 55 amount of turning, changes in course, degree of wandering, inter-val of response and manner of coming to rest, could be obtainedin this apparatus with approximate correctness. To determinethe rate of locomotion, however, required a device which wouldmeasure accurately the distance traveled in a unit of time. The. Fig. 2 ABCF, pantograph; C, fixed point; D, paraffine wall of aquarium; E, plate glass bottomof aquarium; F, place where the arm A is grasped by the operator. A style is located at end ofarm A, in contact with under side of aquarium floor. J, style at end of tracing arm B, in contact withsmoked paper; J, beginning of a course traced on the smoked paper; K, drawing board for attachmentof smoked paper; L, sheet of smoked paper fastened to drawing board; M, actual course of the worm. method already mentioned of measuring rate from mucus-tracksdeveloped by means of powdered carmine, proved too tedious anduncertain except for the worms maneuvers in the dark, when itseemed the only available way. 56 Herbert Eugene Walter To avoid the inconveniences of this method an attachment wasdevised for directly duplicating the path of a worm by means ofa style traveling over a sheet of smoked paper. The records thustraced were made permanent by immersing the smoke
Size: 1576px × 1586px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookidreactionsofp, bookyear1906
