Ductus Stenonis and the exocrine glands.
By Hans Kermit
Steensen’s first anatomical discovery was made at the age of 22 while a student in Amsterdam.
…in the first sheep’s head I bought and dissected myself I found a passage which, so far as I was aware, no-one had previously described. At first I thought I would dissect the brain and so I’d removed the outer tissue when suddenly I got the idea of first examining the ducts which ran through the mouth. I, therefore, conducted a probe through the tissues in order to examine the course of the veins and arteries. Suddenly I discovered that the tip of the probe…was moving freely inside a capacious cavity. When I pushed the probe further down I could hear that it was coming up against the teeth.
This was the discovery of the parotid gland, or ductus stenonianus. Not only did Steensen discover the parotid gland, he recognized it for what it was: a gland that supplied saliva to the mouth.
Steensen was the first to understand thoroughly the role of the glands. In many cases the task of glandular excretions is to ensure a frictionless movement between different issues in the organism. He wrote in an essay that, “the most ingenious of mechanics” lubricates the eye with tears just like an ordinary mechanic lubricates an axle with oil.
Stensen was taken by the thought that wherever moisture exists on the human body it must be the result of glandular secretions. He began, therefore, to look for glands on those parts of the body which are normally moist. Steensen’s discoveries were published in a book entitled Observations on muscles and glands. Steensen’s discoveries were accepted relatively quickly by his contemporaries and made him a famous man. Steensen had, in fact, mapped out most of the human body’s exocrine glands…and in most cases had also explained their specific role.