THE REACTION TO TACTILE STIMULI AND THE 
DEVELOPMENT OF THE SWIMMING MOVE- 
MENT IN EMBRYOS OF DIEMYCTYLUS TORO- 
SUS, ESCHSCHOLTZ.' 
G. E. COGHILL. 
Studies from the Neurological Laboratory of Denison University, No XXII. 
In 1906 I began a series of experiments upon embryos of Rana 
and Amblystoma with a view to determining whether there is any 
regularity in the earliest neuro-muscular responses to tactile stimuli 
in the amphibian embryo. During the season of 1907 these ex- 
periments were continued upon embryos of Diemyctylus torosus, 
Eschscholtz (Triton torosus). Although the work of the first year 
, gave interesting results and convinced me that the field of investi- 
j gation was a fruitful one, it was less exhaustive and critical in its 
methods than the later work has been, and there is no occasion to 
give an account of it in this connection. It will, therefore, receive 
* no further treatment here and all the data and discussions of this 
I paper will relate exclusively to Diemyctylus torosus. 
These experiments were originally planned for correlated ana- 
tomical and physiological studies. As an introduction to such 
work upon Amphibia they form the basis for the anatomical part, 
since they reveal distinct phases in the development of neuro-muscu- 
lar response to the most primitive system of cutaneous receptors. 
But, apart from this significance to pure anatomy and physiology, 
they are, of themselves, an interesting contribution to the science 
of animal behavior, for they deal with a most important phase of 
behavior, namely, its very beginning in the embryo. If, for in- 
stance, there is any such thing as a ‘‘ simple reflex,’’ such as Sherring- 
ton suggests,^ it must be found in the earliest reflexes of the embryo 
as observed in these experiments, and if it is possible to trace the 
^Reprinted from The 'Journal of Comparative Neurology and Psychology. 
vol. xix, no. I, April, 1909. 
^Sherrington, Charles S. The Integrative Action of the Nervous System, p. 8. 
