BEHAVIORISTIC STUDY OF THE RAT 
41 
mated by the following evidence. (1) It is a well-known fact 
that the stomach when completely excised from the body still 
continues to contract very much as before. This excised organ 
will continue to function for a considerable period of time if it is 
kept warm and moist and given the proper nourishment of oxygen. 
(2) Carlson and others have shown that the stomach functions 
quite normally in the body after complete nervous isolation from 
the rest of the body, after section of both vagi and both splancnics. 
Carlson sums up the evidence on this point in this way. . . . 
The essential point is that since the empty stomach, completely 
isolated from the central nervous system, does exhibit the typical 
hunger contractions, the primary role of the gastric nerves is 
that of modifying or regulating essentially automatic mechanisms 
in the stomach wall.” (3) The autonomous function of the 
stomach was further demonstrated by Carlson by means of a 
very ingenious experiment in which he used a Pavlov accessory 
pouch. In this experiment he found that “when the muscularis 
and myenteric isthmus joining the main and accessory stomachs is 
relatively narrow, the two stomachs exhibit complete independ¬ 
ence of the hunger contractions, even to the point of vigorous ac¬ 
tivity of the one during quiescence of the other.” 3 
There remains then the last of the three possibilities; that the 
spontaneous gross bodily activity is due to the activity of the 
stomach. This explanation seems to square best with the facts 
at hand at present on the activity of the stomach and the activity 
of the total organism. There are still so many gaps in our in¬ 
formation regarding both of the subjects that it is not possible 
3 Carlson regards the results of this experiment as very good evidence for the 
independence of the stomach from the stimulation of agents in the blood-stream. 
Carlson argues that the blood can have nothing to do with the stimulation since 
the stomach and the accessory pouch function independently though they are 
both supplied by the same blood. In interpreting these results in this way he 
does not give consideration to the fact of the local rhythms of the different parts 
of the stomach. It is well-known that strips of muscle taken from different parts 
of the walls of the stomach and placed in Ringer solution contract at quite dif¬ 
ferent rates. Every part has its own rhythm. In Carlson’s experiment then the 
possibility still remains that the main stomach and accessory pouch were stimu¬ 
lated by agents in the blood stream, but that because of their different inherent 
rhythms they responded independently. 
