Eight lectures on the signs of life from their electrical aspect eightlectureson00wall Year: 1903 v.] THE SKIN DISCHARGE 83 direct response, is said by Bach and Oehler not to abolish the indirect excitabihty, which presumably depends on deeper parts. We therefore conclude that the main factor of the response is the general epithelial investment â its Malpighian layer in particular. Indirect excitation of the skin through nervous channels presumably arouses the cutaneous glands alone; the general epithelium is, as far as we know, as much outside the control of nerve fibres as are blood-corpus
Eight lectures on the signs of life from their electrical aspect eightlectureson00wall Year: 1903 v.] THE SKIN DISCHARGE 83 direct response, is said by Bach and Oehler not to abolish the indirect excitabihty, which presumably depends on deeper parts. We therefore conclude that the main factor of the response is the general epithelial investment â its Malpighian layer in particular. Indirect excitation of the skin through nervous channels presumably arouses the cutaneous glands alone; the general epithelium is, as far as we know, as much outside the control of nerve fibres as are blood-corpuscles. We cannot, therefore, in comparing the effects of direct and of indirect excitation, regard the comparison as a simple one, like that of direct and indirect excitation of muscle. Thus, in frog's skin, the effect of indirect excitation is often negative (ingoing) when that of direct excitation is positive (outgoing). In cat's skin the effect of indirect excitation is always ingoing, that of direct excitation is at first ingoing, at last outgoing. It would be interesting to see what effect, if any, the two forms of excitation exercise upon each other. I have not found time to do this, although obviously it would be an easy matter to take a regular series of indirect effects, interpolating in the series one or more direct excitations of some convenient duration and strength; or a regular series of direct effects, interpolating in the series one or more indirect excitations. Of course, it would be necessary to photograph the effects; I wonder what they would be ? * * I have since tested this point, as regards the effect of direct upon indirect excitation, in the case of frog's skin, also in the case of the cat {vide infra, Lecture VI.), with the following results :â VoU â¢005-1 â¢004-- â¢003 â OOZ â OOI â 000 Before Fig. 37.âIndirect responses of frog's skin to tetanisation of the sciatic nerve before and after direct excitation of the skin itself by a single stro
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