| Normal. | Reflex. | |||
|---|---|---|---|---|
| Frog. | Average for 20 reactions. | Mean Var. | Average for 20 reactions. | Mean Var. |
| A | 149.5σ | 24.0σ | ||
| B | 158.3 | 16.0 | 51.5σ | 8.0σ |
| C | 191.0 | 24.3 | ||
| D | 167.0 | 10.1 | ||
| E | 182.4 | 28.0 | 45.1 | 5.5 |
| F | 176.3 | 10.2 | 46.0 | 4.5 |
| General Average. | 167.9σ | 18.8σ | 47.5σ | 6.0σ |
For D the average is for ten reactions.
B and E were males, F a female; the sex of the others was not determined by dissection and is uncertain.
Early in the experiments it became evident that there were three clearly defined types of reactions: there were a number of reactions whose time was shorter than that of the ordinary quick voluntary pain reaction, and there were also many whose time was considerably longer. The first type it was thought might represent the spinal reflex reaction time. For the purpose of determining whether the supposition was true, at the end of the series of experiments three of the frogs were killed and their reflex reaction time noted. This was done by cutting the spinal cord just back of the medulla, placing the animal on an experimenting board close to the reaction key with the thread from the key fastened to the left leg as in case of the previous work and stimulating the gastrocnemius with an induced current by the application of wire electrodes.
In Table IX. the reflex reaction times for the three animals are given.
The following results obtained with frog E show that the time of reaction increases with the increase in the time after death. The average of 20 reactions by E taken an hour after the cord had been cut was 45.5σ; the average of 20 taken twenty hours later was 55.85σ.
As a rule the reflex reactions were but slightly variable in time as is indicated by the accompanying series.
SERIES OF REFLEX REACTIONS OF FROG F.
Taken at rate of one per minute.
| 1 | 50σ |
| 2 | 58 |
| 3 | 55 |
| 4 | 59 |
| 5 | 48 |
| 6 | 46 |
| 7 | 45 |
| 8 | 51 |
| 9 | 42 |
| 10 | 44 |