312 SECRETS OF ANIMAL LIFE 
esting is that the changes thus induced “ by idea- 
complexes, formed and maintained without any 
emotion” are small compared with those brought 
about by conditions predominantly emotional. 
Dr. Dearborn has worked at the factors altering 
blood pressure, and he makes the notable statement 
that in the “general stimulation of the essential 
circulation in all constructive parts of the body, 
such as the brain, the muscles, and the digestive 
organs, joy exerts one of its most conspicuous 
benefits, and one that no one can doubt or ignore.” 
It is interesting to ask, though we may never be 
able to answer, whether the apparent joyousness 
of many birds, expressed especially in song, but 
also in dance and exuberant flight, is correlated 
with their singularly perfect digestive capacity, 
their fine circulation and muscularity. If birds 
have no genuine joie de vivre, they make at times 
an extraordinarily good imitation of it, and we 
should like to know whether they are eupeptic 
because they are joyous, or joyous because they 
are eupeptic. For sometimes an organism is a 
mind-body and at other times a body-mind. 
For man, however, there is no doubt that affective 
states of joy and grief cause rapid changes in blood 
pressure. ‘In one case,’ Dearborn tells us, “an 
imaginary kiss caused in ninety seconds a rise of 
at least twenty millimeters of mercurial pressure; 
while in another individual a suddenly recalled 
grief raised it in less time thirty per cent. more than 
that.” A large variation in blood-pressure in 
