1. A convenient isolated preparation of the lateralis organs and nerve of Xenopus laevis is described. An average of two active units can be obtained by cutting between the groups of organs in the skin.

2. There is a basic discharge, which is irregular and which varies directly with steady temperatures.

3. An opposite response is obtained to temperature changes. On cooling there is an increase in frequency adapting to the new steady level with a time-constant of 20 sec., and on warming there is a corresponding decrease in frequency.

4. The threshold for temperature change is 1-2° C., representing a rate of change of temperature of 0.3-0.6° C./sec. at the surface of the skin.

5. In the more sensitive preparations the basic frequency is doubled or completely inhibited by a change of 5° C.

6. The threshold change of temperature for similar preparations of skin and segmental cutaneous nerve is 5-10° C.

7. The discharge frequency can be increased by mechanical stimulation, but only at intensities high enough to act at the nerve endings directly and not by way of the sensory cells. The sensitivity is comparable to that of the segmental cutaneous nerves.

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