. Studies in general physiology. Physiology; Phototropism; Geotropism; Reproduction; Irritability; Regeneration (Biology). Beain Physiology op Worms 347. FIG. 98 Schrader has found that a frog is possessed of an irresistible impulse to move after losing this center.' The simplest facts of comparative physiology show more- over that the power of progressive movement is possessed also by such organisms which have no brain whatever, ('. e., the swarm spores of Algse. It is, in my opinion, not the problem of physi- ology to find a definition for an organ but to discover the functions of a given or
. Studies in general physiology. Physiology; Phototropism; Geotropism; Reproduction; Irritability; Regeneration (Biology). Beain Physiology op Worms 347. FIG. 98 Schrader has found that a frog is possessed of an irresistible impulse to move after losing this center.' The simplest facts of comparative physiology show more- over that the power of progressive movement is possessed also by such organisms which have no brain whatever, ('. e., the swarm spores of Algse. It is, in my opinion, not the problem of physi- ology to find a definition for an organ but to discover the functions of a given organ. From this standpoint I wish to make in the following pages some contribu- tions to the brain physiology of worms. I understand in this paper by the term brain, as is customary, the ganglia lying at the oral end of these animals. Brain physiology has shown that for the higher animals the biologi- cal character of a species, that is, the sum total of those reactions of a species which are determined by the external surroundings, depends chiefly upon the brain. I was espe- cially interested in determining whether the rudimentary brain of such low animals as the worms has a similar signifi- cance. The experiments which I wish to report have been made at long intervals, some in Naples in 1889, some in Woods Hole in 1893. II I. EXPERIMENTS ON THYSANOZOON BBOCCHII 1. Thysanozoon is an elliptically shaped marine Planarian (Fig. 98, according to Lang), which is from one to three cm. long, and almost as broad. The brain g of the animal, an unpaired organ, is situated at the anterior extremity of the body, which latter can be recognized without difficulty by 1SCHKADER, PflUgers Archiv, Vol. XLI. Digitized by Microsoft®. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Loeb, Jacques, 1859-1924. Chicago, The Univers
Size: 1343px × 1860px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubje, booksubjectphysiology
