INTERRELATIONS OF SECRETIONS 49 
depends on the secretory activity and stimulation of 
others, is shown by the fact that in hypothyroidism in 
children there is slow growth and development. Also 
in hyperthyroidism it has been found that the most 
severe types often are accompanied by enlargement of 
the thymus. Retarded sexual development and quick, 
prolonged growth before maturity is also coincident to 
enlargement of the thymus and feeding with the ex- 
tract (10). Then the anterior lobe of the pituitary 
body has also an effect on growth, abnormal amounts 
producing giantism or acromegaly, while a lessened 
production retards growth and maturity. The feeding 
of tadpoles with thyroid gland produces dwarfism but 
quick maturity, which is the direct opposite of the re- 
sults of experimental thymus feeding. 
These facts show that it is hardly possible that a sin- 
gle gland can be at fault in metabolic disturbances, but 
that the hypothesis must be accepted that a great many 
internal secretions enter into the equation. Clinically 
there has been decided improvement in certain back- 
ward children following therapy with a single extract, 
like pituitary or thyroid. Even then it is more rea- 
sonable to suppose that both are more or less involved 
in the disease [and that pluriglandular therapy is even 
better.—H.R.H.]. The reason for the improvement is 
that the feeding with pituitary extract adds its hor- 
monic influence to the thyroid and thereby stimulates 
its production, and vice versa. Other influence is also 
felt, as the rest of the glands are also stimulated to 
secretion, for the output of adrenin is enhanced, which 
can be seen by the rise in blood pressure, which is 
practically always low in cretins. 
The maturing of the sexual glands also follows the 
introduction of the above secretions. The feeding of 
one gland having such a marked effect on the whole 
has led us into the error of classifying endocrine dis- 
ease as due to the disturbance of a single gland, and 
