48 
CURT P. RICHTER 
VIII. RELATION OF SPONTANEOUS ACTIVITY TO HUNGER 
The intimate relation of gross bodily activity and the 
action of the stomach was pointed out in the previous chapter. 
There still remains the question as to the relation of this gross 
bodily activity to the hunger reactions of the animal. Does it 
follow that because this diffuse form of activity is due to the 
stimulation from the stomach that it must all necessarily be 
translated into hunger reactions, searching for food, eating, etc.? 
It was shown that each of the regularly recurring periods of gross 
bodily activity is connected with simultaneous periods of activity 
of the stomach. Is all of the activity in each of these periods 
hunger activity? 
In order to answer these questions and a number of allied ques¬ 
tions a simple construction was used, the ‘double cage.’ This 
arrangement consists of an ordinary triangular activity cage with 
a hole cut in one side large enough to permit of the easy introduc¬ 
tion, without contact, of the snout of an inverted pipe-shaped 
smaller tube containing food. Both cages were supported on a 
separate set of tambours and the activity in each cage was regis¬ 
tered separately. A photograph of the double cage is shown in 
figure 22. The small round cage contains a metal food receptacle 
which is so constructed that the food may be easily gotten at 
through the hole at the top large enough to accommodate the 
head of the rat, but too small to permit the rat to pick up food in 
its paws and to scatter it about or possibly even to take some of it 
back into the other cage. In this experiment food was left in 
the food receptacle all the time, and water was left in the water- 
glass attached to the outside of the triangular cage. Of course, 
there is an obvious possibility of the animal's entering the food 
box for other purposes than replenishing itself with food. In 
order to eliminate this possibility the food cage was made just 
human uterus. This organ, especially in multiparous women, continues to con¬ 
tract for a number of days after the birth of the child. The contractions are 
originally set up by the presence of the foetus. All during pregnancy these con¬ 
tractions go on. But interestingly in this connection they are not felt until 
labor begins, when they serve to expel the foetus. After labor they still continue 
to be felt for a number of days (that is they are still strong enough to dominate the 
organism). 
