On Projection as a Possible Source of Apparent Color in Sunspots

Abstract

The rate of flagellar vibration of sperms was studied by mounting human sperms in spermatic fluid at 32[degree]C and observing in the dark field, illuminated by stroboscopic light. The sperm cell does not move forward at a steady rate, nor does the tail beat with a simple harmonic motion. It progresses in irregular jerks, each burst of speed lasting less than a second. Despite variability in readings, it was noted that the tails of human sperm cells have a frequency of beat which is close to that of the cilia or flagella of clam gills or monads; this is due to the fact thaty they are of the same order of magnitude.