oye 27) ar eee paws. Te Ss 
PRESIDENT’S ADDRESS. 29 
system (Langley). In this manner the importance of their integrity 
has been explained, although we have still much to learn regarding 
their functions. 
Another instance of an internally secreting gland which is essential 
to life, or at least to its maintenance in a normal condition, is the 
thyroid. The association of imperfect development or 
disease of the thyroid with disorders of nutrition and inac- 
tivity of the nervous system is well ascertained. The form of idiocy 
known as cretinism and the affection termed myxcedema are both asso- 
ciated with deficiency of its secretion: somewhat similar conditions to 
these are produced by the surgical removal of the gland. The symptoms 
are alleviated or cured by the administration of its juice. On the other 
hand, enlargement of the thyroid, accompanied by increase of its 
secretion, produces symptoms of nervous excitation, and similar symp- 
toms are caused by excessive administration of the glandular substance 
by the mouth. From these observations it is inferred that the juice con- 
tains hormones which help to regulate the nutrition of the body and 
serve to stimulate the nervous system, for the higher functions of which 
they appear to be essential. To quote M. Gley, to whose researches we 
owe much of our knowledge regarding the functions of this organ: * La 
genése et l’exercice des plus hautes facultés de l'homme sont con- 
ditionnés par l’action purement chimique d’un produit de sécrétion. 
Que les psychologues méditent ces faits! ’ 
The case of the parathyroid glandules is still more remarkable. 
These organs were discovered by Sandstrém in 1880. They are four 
minute bodies, each no larger than a pin’s head, 
imbedded in the thyroid. Small as they are, their internal 
secretion possesses hormones which exert a powerful influence upon 
the nervous system. If they are completely removed, a complex of 
symptoms, technically known as ‘tetany,’ is liable to occur, which 
is always serious and may be fatal. Like the hormones of the 
thyroid itself, therefore, those of the parathyroids produce effects upon 
the nervous system, to which they are carried by the blood; although 
the effects are of a different kind. 
Another internally secreting gland which has evoked considerable 
interest during the last few years is the pituitary body. This is a small 
structure no larger than a cob-nut attached to the base of 
the brain. It is mainly composed of glandular cells. Its 
removal has been found (by most observers) to be fatal—often within 
two or three days. Its hypertrophy, when occurring during the general 
growth of the body, is attended by an undue development of the skeleton, 
Thyroid. 
Parathyroids. 
Pituitary. 
‘so that the stature tend§ to assume gigantic proportions. When the 
hypertrophy occurs after growth is completed, the extremities—viz., the 
hands and feet, and the bones of the face—are mainly affected ; hence 
