DR. H. WATNEY ON THE MINUTE ANATOMY OF THE THYMUS. 
.1065 
Kurus op Ephesus (4) first mentioned the thymus, and noticed that it cannot he 
found in all bodies. 
Galen (5) said that the organ has attained its greatest size in newly born animals, 
and diminishes after birth. 
This view, that it decreases very rapidly after birth, seems to have been held from 
this time until the latter half of the seventeenth century ; although Mobius (6) 
noticed a thymus in the post-mortem examination of a man thirty years old. 
Glisson (7), 1671, found that it is large in children. 
Mangetus (8), 1717, said that the gland is very large in newly born children, but 
decreases during childhood. 
Vekheyen (9), 1726, was the first who definitely presented the fact that the 
thymus grows after birth. He said that it is larger in children some years old, than 
in those newly born. 
Hewson (10), 1777, said that the gland enlarges to the end of the first year ; and 
since his time it has been generally accepted, that the growth of the gland is not 
terminated by the duration of foetal life. 
It was in the end of the seventeenth century that two anatomical statements were 
put forward, both of which delayed for a long time a more extended knowledge of 
this organ. One statement was as fruitful a source of physiological error as the other 
was of anatomical misconception. 
In 1670, Velsch (11), in the Alpine Marmot, confounded the fat glands and the 
thymus. This confusion between fat glands and thymus, which was a very natural 
one, was continued by Harder (12), Scheuchzer (13), Pallas (14), Meckel (15), 
Prunelle (16), and Tiedemann (17). It was in consequence of this error that 
Pallas (14) in 1778 compared hibernation to foetal life. Cuvier (18) noticed that 
the thymus and other glands diminish the capacity of the chest in hibernating 
animals. In 1817, however, Jacobson (19) showed that the glands in the thorax, 
which enlarge in the winter sleep, are not thymus ; and that the thymus behaves in 
animals which hibernate, as in other animals; and maintained that the thymus has 
nothing in common with the peculiar glands lying in its neighbourhood, either in its 
development, appearance, or secretion. He was followed by Kudolphi (20) and 
Haugsted (1), the latter giving drawings of the two organs at various periods of life ; 
and the facts were further confirmed by Barkow (21) and others. Simon (2), 
however, accepted the older doctrine, holding that the thymus is very large in hibernat¬ 
ing animals, and he partially founded upon this supposed fact his view of the function 
of the organ. 
The second error arose, as has been stated, about the same time. In 1673, 
Bartholinus (22) asserted that the thymus contains a cavity; and a great part of 
many subsequent anatomical researches were taken up with the various accounts of 
this cavity, the openings into it, and other supposed facts about it. The existence of 
a cavity was accepted by Hugo (23), who worked with Haller, by Lucae (24), by 
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