The relation between spectral color and stimulation in the lower organisms

✍ Scribed by S.O. Mast

• Publisher: Elsevier Science
• Year: 1915
• Tongue: English
• Weight: 159 KB
• Volume: 180
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/s0016-0032(15)90547-1

✦ Synopsis

IT is well known that many of the simplest organisms respond very definitely to light. Some orient and travel fairly directly toward the light, others away from the light, while still others go toward it under some conditions and away from it under others.

In a field of light consisting of two horizontal beams crossing at right angles these organisms proceed toward or from a point situated between the two beams. The location of this point depends upon the relative effective luminous flux illumination received by the organisms from these beams. If it is the same in quality and intensity, so that the stimulation is the same, the point lies approximately half way between them. 1 Consequently whenever the organisms proceed toward or from a point thus located it may be concluded that the stimulating effect of the light in the beams is equal, no matter how it may differ, either in intensity or in quality. 2 It is therefore obvious that if the light in one beam is kept constant in quality (white, for example), while that in the other is changed in color, the relative stimulating efficiency of the different colors can be ascertained. To do this, all that is necessary is to vary the luminous intensity of the white light for each change in the colored light, until, in each case, the organisms proceed on the same path. The stimulating effect of the different colors will then be directly proportional to the various luminous intensities of the white light required to make the organisms under each of the different conditions proceed in the same * Communicated by the Director. 1Details as to the process of orientation in these organisms may be found in my book on " Light and the Behavior of Organisms," John Wiley & Sons, New York, IOII.