. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 450 JAMES CASE AND G. F. GWILLIAM adapt mechanoreceptors as much as possible. During all experiments the prepara- tion was frequently tested with Mytilus extract (prepared by grinding the soft parts of a Mytilus in about 25 ml. of sea water) or .001 to .005 M 1-glutaniic acid and dis- carded once responses to these fell below initial magnitudes. Ordinarily, dete- rioration of the preparation presented little difficulty. With reasonable care a chemoreceptor bundle remained in satisfactory condition for an hour or longer. Resp
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 450 JAMES CASE AND G. F. GWILLIAM adapt mechanoreceptors as much as possible. During all experiments the prepara- tion was frequently tested with Mytilus extract (prepared by grinding the soft parts of a Mytilus in about 25 ml. of sea water) or .001 to .005 M 1-glutaniic acid and dis- carded once responses to these fell below initial magnitudes. Ordinarily, dete- rioration of the preparation presented little difficulty. With reasonable care a chemoreceptor bundle remained in satisfactory condition for an hour or longer. Responses of the dactyl chemoreceptors to test substances were evaluated by comparing the activity induced by a drop of the test substance with the effect of a drop of .001 M 1-glutamic acid. Data were evaluated from film records and by direct aural and visual comparisons of oscilloscopic activity. For purposes of tabu- lation these responses were recorded on a scale of 4 in which 0 was equal to a response indistinguishable from the effect of a drop of sea water and 4 was equal to the effect of .001 M 1-glutamic acid. RESULTS 1. General In nearly all preparations many nerve fibers could be isolated which mediated responses to Mytilus extract. Except in rare instances these were difficult to isolate. FIGURE 1. Dactyl of first walking leg of Carcinides inacnas. from larger fibers carrying mechanoreceptor impulses. Indeed, there is every possibility that at least some of the chemoreceptor units themselves may respond to mechanical stimulation, although it is clear from our data that not all do. In prac- tice, the nearly unavoidable mixing of the two types of activity was not particularly bothersome since the mechanoreceptor responses were of short latency and adapted rapidly, while the slowly adapting chemoreceptor units had considerably longer latency, ranging from 15 to 250 mscs., measured from the first mechanoreceptor spike and varying inversely with stimulant concentration. The n
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
