40 
CURT P. RICHTER 
In humans however it has been possible to demonstrate this 
simultaneity of the contractions of the stomach and gross bodily 
movements. Miss Tomi Wada took simultaneous records on 
medical students of gross bodily movements and stomach con¬ 
tractions during sleep. The stomach contraction records were 
obtained by the usual method employed by Cannon and Carlson. 
The subjects swallowed the balloon and tube just before going to 
bed. The record of the gross bodily movements was obtained 
by means of a simple system of tambours placed under the bed. 
Records were taken during sleep because during the waking- 
periods the subjects are exposed to many external stimuli, and 
it is not possible to differentiate the part of the activity which is 
due to these external stimuli from the part that is spontaneous. 
Miss Wada found that the spontaneous movements during sleep, 
what few there are, rolling over in bed, etc. come periodically 
in regular groups. Miss Wada found further that in every 
case these periods of gross bodily activity coincided with the 
activity periods of the stomach. During the intervals between, 
when the stomach is quiescent, the body is also completely quiet. 
These results leave little doubt about the simultaneity of gross 
bodily movements and the activity of the stomach. 
Up to this point it has been shown that the stomach con¬ 
tractions and the periods of spontaneous bodily activity in all 
probability occur simultaneously. In any case of this kind where 
two phenomena occur simultaneously in this way the following 
possible explanations of the causal sequence may be made. (1) 
either both are due to some other common agent, (2) or else the 
bodily activity is the cause of the stomach activity (3) or finally 
that the stomach activity is the cause of the gross bodily activity. 
One of these explanations is easily eliminated; that the stomach 
activity is due to gross bodily activity. It is an experimental 
fact easily verified that contractions of the stomach cannot be 
elicited in anyway by activity of the whole body, rather on the 
contrary bodily activity tends to inhibit the contractions (Carlson 
and others). 
The second possibility that the stomach contractions and the 
activity have a common origin, a common stimulus may be elim- 
