OUR KNOWLEDGE OF THE ENDOCRIN GLANDS
The first physiologist to arouse any widespread interest among his fellow medical men in these small ductless glands was a Paris physician, Brown-Sequard. The experiments which he performed and the theories which he propounded have, for the most part, been disproved, but the enthusiasm which went into his investigations was soon caught by other scientists. In the last forty years masses of data have been collected which have thrown an increasingly brighter light on this subject which until comparatively recently was completely shrouded in darkness. Today candidates for medical degrees must have as full and up-to-date knowledge of the endocrin system as they have of the action of the heart and lungs and the disorders of digestion. Psychiatrists prescribe glandular treatments as supplements to their mental analyses. And attendants at feeble minded institutions and social workers must learn to recognize distinctive glandular types.
There have been two methods of gathering information about these glands whose importance for medicine and for psychiatry is becoming greater and greater: the clinical and the experimental. In the experimental method, which gives the more accurate results, animals are used as subjects. A certain gland is removed from a certain animal and then his growth, his movements, his whole life history subsequent to the operation is carefully noted and compared to the life histories of normal animals of the same species. Or the extract from another gland is injected into the blood stream of another animal and his behavior after the injection correlated with that of his fellows.
Human beings, of course, cannot be experimented upon in this ruthless fashion, but medical clinicians have found that nature, herself, has in many cases already done a good bit of experimenting. Some individuals are born with one or another of their endocrin glands either smaller or larger or more or less active than is customary. Several of these glands grow so close to the surface of the body that any abnormality of them can be easily seen. Others, which are more securely hidden, can be detected by the X-ray. And it has been discovered that whenever an endocrin gland is exceptionally large or small or extremely active or noticeably sluggish, the individual in whom this abnormal condition occurs will exhibit other peculiarities, either of physical or mental development—most likely of both.
From these two sources, the clinic and the animal laboratory, some very definite information about extreme types of personality has been obtained, and the knowledge in many cases has been carried over to explain commoner but even more interesting variations of normal personality.