BIOLOGY AND MEDICINE—CHANDLER 325 
self from injection of gland extracts. His results, too, were prob- 
ably psychological, but his prestige was such that his claims started 
a development in medicine that has had more profound significance 
than any since Pasteur’s discoveries of the bacterial origin of disease. 
The human body is a highly automatic, self-regulating mechanism. 
Nature’s primitive means of regulation of the body of an organism is 
by chemical substances secreted by its tissues. Superimposed on this, 
later in evolution, is an involuntary nervous system, useful in making 
rapid and temporary adjustments that become necessary for a body 
with ever-increasing activities and more and more complicated rela- 
tions to its environment. Still later in evolution Nature added a 
voluntary nervous system but very wisely refrained from giving it 
control over the internal regulation of the body. As Dr. Cannon 
remarks, we should be greatly bothered if in addition to attending 
to the business of other people we had to attend to our own. The 
internal affairs of the body are too important to be subject to a well- 
meaning but neglectful and incompetent intelligence, which would 
as likely as not be concerning itself with the flight of a golf ball when 
it ought to be attending to the rate of the heart beat. 
The chemical method is still the fundamental means of regulation of 
the body. Chemicals produced by tissues, which we call hormones, con- 
trol such functions as growth, development, metabolism, and reproduc- 
tion, and adapt the body gradually to climatic fluctuations, variations 
in activity, nutritional changes, pregnancy, lactation, etc. The human 
body is one of the most thoroughly integrated and communistic or- 
ganizations imaginable, every part sharing, according to need, with 
every other part, and each part influencing every other part. It is a 
prevalent view today that every tissue and organ in the body produces 
hormones or hormonelike substances that help in the integration of the 
entire organism. As bodies became more complex during the course 
of evolution, however, and the regulation more difficult, a number 
of special glands for production of particularly potent hormones were 
developed. These are what constitute the endocrine system. Some of 
the glands are completely separate organs having no other functions, 
such as the thyroid, pituitary, and adrenals. Others have developed as 
special tissues in already existing organs, as in the pancreas, liver, 
and sex glands. 
The potency of these glands is almost incredible. They very largely 
determine what we are and how we behave. They dominate our physi- 
cal stature, our mental development, our emotional status, our repro- 
ductive activity, the rate at which we live, and our ability to make 
use of our food. They are the architects of our bodies and the mould- 
ers of our character. A puppy deprived of its anterior pituitary gland 
may be converted from an aggressive, pugnacious creature to a whimp- 
