42 
CURT P. RICHTER 
at this time to be quite certain of any explanations of how the 
organism works. The investigations in recent years of Cannon 
and Carlson on the sensation of hunger and its relation to the 
stomach contractions have rather definitely established the fact 
that these contractions precede the hunger sensations in time, 
that they are the origin of these sensations. The results obtained 
in the present work seem to show that the stomach contractions 
do not alone bring about sensations of hunger, but they also 
bring about movements of the entire organism by means of which, 
as it will be shown in the following chapter, the organism is 
brought into contact with the materials necessary for stopping 
the contractions. 
A very important gap in our knowledge regarding the relation 
of the action of the viscera to the reactions of the whole organism 
was recently filled in by the work of Carlson and Luckhardt (8) 
on the visceral nervous system of frogs and turtles. In this work 
it was definitely established that stimulation of the visceral 
organs brings about reactions of the skeletal muscles, reactions 
of the whole organism. 1. “ Mechanical or electrical stimulation 
of the lungs, the gall bladder, the heart, the urinary bladder and 
the entire intestinal tract induces skeletal reflexes both in de¬ 
cerebrated and purely spinal preparations. 2. These visceral 
skeletal reflexes, at least as regards the extremities, are essentially 
of the defensive or escape type. ” 4 
The facts obtained in the present work on spontaneous activity 
and the facts known from physiological work on the stomach may 
tentatively be formulated in the following way: There is a 
tendency in all living organisms to maintain a metabolic balance 
or equilibrium. The various substances of the body are present 
in a fairly definite quantitative relationship. Whenever the 
balance is destroyed there is an immediate reaction to reestablish 
it. During fasting or during any time when the stomach is 
empty and the body is in need of nourishment this balance is 
temporarily destroyed. There is a minus of some substances and 
4 We found recently in a series of experiments on the behavior of foetuses (cats) 
still attached to the cord that stimulation of the stomach or intestine (slight 
pinching) elicits very vigorous movements of the entire body. 
