We regularly despair at science and medicine seemingly missing so much about thyroid physiology and processes. However, every so often, we see something so extraordinarily odd and bizarre, we actually seem to have made huge progress.
This starts fairly sensibly. Then goes downhill. Fast.
And remember that 1941 is within the lifetime of many people. It really was not that long ago.
The thyroid gland is present in all vertebrate animals beginning low down in the scale, with the lampreys and complicating its structure and increasing its size as it occurs farther up in the evolutionary scale. In fish the thyroid occurs as small scrubby patches little larger than pin heads scattered along the important blood vessels. Then in the reptiles it is a little larger and more compact, and still more prominent among the birds and the mammalia. But it is in the primates and in man that it attains to greatest size. Thus it might be said that the thyroid gland is an indicator of evolution
The farther we are from our early home in the sea the larger the thyroid gland. Now if evolution continues along the same line, a million years from now our thyroid may have become the most important organ in our bodies. And man’s appearance may be consequently so changed that instead of being the good looking creature he thinks he now is, he will have evolved into a pop-eyed, fat-headed, chinless creature, the space between his chin and his collar button having been taken over by his constantly expanding iodine plant.
American Journal of Pharmacy and the Sciences Supporting Public Health 1941-12: Vol 113 Iss 12
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PS: The thyroid of a beluga whale is around one-third to three-quarters of a litre in volume. So primates certainly are not the thyroid size champs! Just imagine how big their thyroids would be if they lived a long way from the sea, maybe atop Himalayan mountains...