. The physiology of the Invertebrata. face de section neproduit plus de contraction musculaire, alors que la memeexcitation appliquSe sur un point plus rapproch^ du muscley provoque de violentes secousses. These experimenters have shown that the nerves of Homaruspresent the same distribution of electric tensions, and thesame negative variation, as those of the frog (Bana). They have also ascertained the rate of transmission of motor nervous infiux in the nerve connected with the flexor muscle of the dactylopodite. In these experiments they had recourse to the graphic method employed by Helmhol
. The physiology of the Invertebrata. face de section neproduit plus de contraction musculaire, alors que la memeexcitation appliquSe sur un point plus rapproch^ du muscley provoque de violentes secousses. These experimenters have shown that the nerves of Homaruspresent the same distribution of electric tensions, and thesame negative variation, as those of the frog (Bana). They have also ascertained the rate of transmission of motor nervous infiux in the nerve connected with the flexor muscle of the dactylopodite. In these experiments they had recourse to the graphic method employed by Helmholtz. By * Bulletins de VAcacUmie Boy ale de Belgique, 2 serie, t. 47 [1879]. 332 PHYSIOLOGY OF THE INVERTEBRATA. exciting the nerve at a point near the muscle, and notinmoment of excitation and the moment of contraction, (able to ascertain the time which, elapses between th(phenomena: the same experiment is then repeated on aof the nerve further from the muscle. The difference itime observed in these two experiments—that is to sa; P. Fig. 66.—Apparatus foe Studying the Transmission of MotiExcitation in the Nerve of the Chela. M = myograph carrying claw of Homarus. s = style attached to theopodite. r = elastic spring which holds the dactylopodite. a = electrodes, b = another pair of electrodes. C = commutator. P = 1E = registration cylinder. BB = the two coils. A = steel needles forthe circuit at each revolution of the cylinder. lapse of time between the second contraction and the f gives the time employed by the motor excitation to rn distance between the two excited points. Knowing distance, one can calculate the rate of transmission. Predericq and Vandevelde exposed the nerve (in a lobster) which leads to the claw by two openings. A i * The style used was that of Dr. Marey, the distinguished ProfeiExperimental Physiology in the College of France. PHYSIOLOGY OF THE INVERTEBRATA. 333 was attached to the dactylopodite o£ the chela (Pig. ()€)^ andall firmly fixed, by the ai
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectinverte, bookyear1892
