. Jelly-fish, star-fish and sea-urchins [microform] : being a research on primitive nervous systems. Nervous system; Jellyfishes; Starfishes; Sea urchins; Nerveux, Système; Méduses; Astérides; Echinides. 11! 9J? JELLY-FISH, STAR-FISH, AND SEA-URCHINS. the strip in this way, the latter might be gently strained throughout its entire length, the degree of straining being dei'^rmined by the height out of the water to which the tissue was raised. Of course, if the strip is too greatly strained, the contraction- waves become blocked altogether, as described above; but shortly before this degree of s
. Jelly-fish, star-fish and sea-urchins [microform] : being a research on primitive nervous systems. Nervous system; Jellyfishes; Starfishes; Sea urchins; Nerveux, Système; Méduses; Astérides; Echinides. 11! 9J? JELLY-FISH, STAR-FISH, AND SEA-URCHINS. the strip in this way, the latter might be gently strained throughout its entire length, the degree of straining being dei'^rmined by the height out of the water to which the tissue was raised. Of course, if the strip is too greatly strained, the contraction- waves become blocked altogether, as described above; but shortly before this degree of straining was reached, I could generally observe that the rate of the waves was diminished. To give one instance, a contractile strip measuring twenty-two inches had the rate of its waves taken before and after strain- ing of the kind described. The result was as follows:— Before After straining ... One second. Fig. 11. Immediately after severe handling of this kind, the retardation of contraction-waves is sometimes even more marked than here represented; but I think this may be partly due to shock, for on giving the tissue a little while to recover, the rate of the waves becomes slightly increased. Ansesthetics likewise have the effect of slowing the rate of contraction-waves before blocking them. Taking, for instance, the case of chloroform, a narrow spiral strip between one and two feet long was immersed in sea-water containing a large dose of the anaesthetic; the observations being taken at six seconds' intervals, the following were the results:—. 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 Romanes, George John, 1848-1894. London : K. Paul, Trench
Size: 3253px × 768px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdeca, booksubjectnervoussystem, bookyear1895
