430
IL P. BOWDITGH AND J. W. WARREN.
horizontal line below the curve correspond to minutes.) Slighter and
less frequent changes in the size of the leg were not at all unusual, and
were at times quite inconvenient, as they interfered with the interpre¬
tation of the experiments. These changes consisted generally in a
rather rapid dilatation followed by a slow return to the normal size,
though at times a contraction seemed to be the primary phenomenon.
An example of the automatic changes such as were most frequently met
with is given in fig. 5. In fig. 6 are shown similar curves obtained
simultaneously from both legs, the left sciatic nerve having been
Fig. 5.
Reduced one Half from the original.
divided three days and the right about two hours before the tracings
were made. It will be noticed that the curves are, in a general way,
parallel to each other, showing that the causes of the variations are
not local. Whether they are due to changes in the action of the heart
or to alterations in the capacity of a collateral vascular area, e.g. the
viscera, is a question which cannot be decided by any data furnished by
our investigations.
The individual differences between cats in respect to the character
and energy of these vaso-motor phenomena will be still more strikingly
shown in the discussion of the results of electric stimulation of the
sciatic nerve. In this connection it is of interest to note that
Kowalewsky1 found that, in these animals, the division of the lateral
columns of the cord or of the cervical sympathetic did not always
produce uniform results.
1 GentraUilatt für die Med. Wiss. 1885, a. 307.