30 LIFE: ITS ORIGIN AND NATURE 
muscle cells, and affects the brain and sex tone, 
(c) The adrenals. These are the glands of com¬ 
bat, and are stimulated whenever the fighting 
instinct is brought into play. The adrenals are 
subdivided into two portions, (1) the “cortex,” 
secreting a substance as yet unknown, but which 
seems to affect the growth of the brain and the 
sex glands. (2) The “medulla,” secreting 
“adrenalin,” which substance imparts to the 
body energy for emergency situations, (d) The 
pineal gland. The precise nature of its secre¬ 
tion is unknown, but it seems to control the 
development of pubity, and affect brain and sex 
development, (e) The thymus gland. This is 
the gland of childhood; the nature of its secre¬ 
tion is as yet unknown. It seems to prevent 
too rapid maturity, and gradually disappears 
after pubity. (f) The gonads, or sexual glands. 
These, apart from their obvious functions, seem 
to govern the excitability of muscle and nerve, 
and also to control, to a great extent, the lime 
metabolism in the body, (g) The pancreas. 
This gland secretes a substance known as “in- 
suline,” and controls the sugar metabolism of 
the body. 
It has been contended by certain authors 
( e. g., Dr. Louis Berman, in his book “The 
Glands Regulating Personality”) that the duct¬ 
less glands, in addition to these purely 
physiological functions, also control, to a great 
extent, the character of the mental or psychic 
life; and that one’s temperament, moods, 
emotions, and even the very personality itself is 
to a large extent governed and controlled by the 
activities and secretions of these glands. There 
