48 THE INTERNAL SECRETIONS—1920 
this way can this balance be explained. For instance, 
an increase of the thyroid secretion does not always 
manifest itself immediately. Some time elapses before 
clinical signs develop, and even then the basal meta- 
bolic rate is often maintained. Without increased ac- 
tion of other glands, stimulated by the presence of 
thyrotoxin, all cases of thyrotoxic adenoma would 
show disturbance of metabolic rate immediately and 
constantly, which is not the case. In such cases an 
excessive stimulation is given to the adrenals, for in 
these adenomata the first sign is often a rise of blood 
pressure (6). This stimulation is kept up until bal- 
ance is definitely lost, and then the clinical symptoms 
manifest themselves. The balance is lost only when 
the other associated glands cannot keep up with the 
abnormal gland. Then the picture is not only that of a 
predominating thyrotoxic element, but an augmenta- 
tion of symptoms through overproduction of other in- 
ternal secretions, notably the ovaries and adrenals (7). 
At times this interrelationship is hard to deter- 
mine except empirically, but the hypothesis is well 
borne out that in cases of hyperthyroidism the balance 
is not only kept for some time, but the feeding of co- 
operative endocrine products, like thymus, adrenal or 
pituitary extracts, seems to alleviate symptoms (8). 
After the stage of high blood pressure comes myocar- 
ditis through loss of muscle tone. Here the stimulus to 
adrenals and pituitary has been so great that they have 
become exhausted. This exhaustion of the adrenals 
makes it ofttimes necessary to give treatment with 
adrenalin before the operation for thyroidectomy, in 
order to improve the heart tone. For the same reason 
after-treatment, this time with adrenal substance, fol- 
lowing severe cases, has to be long-continued because 
of this exhaustion (9). 
That this hormonic action and interaction is constant 
and necessary, and that development of some glands 
