12 
Transactions Texas Academy oe Science. — 1907. 
arrested, either spontaneously or artificially (by operation). On the 
contrary, diminished secretion produces a disease known as “myxoedema,” 
which is characterized by symptoms the direct antithesis of the former, 
viz., sluggish intellect and slow, weak pulse; a disease which in its turn 
ends fatally, unless thyroid secretion is supplied artificially. 
Again, at different periods of life, the thyroid secretion subserves 
different needs. In early life it seems to be necessary as a stimulant 
to the growth of the common tissues, such as bone and the connective 
tissues; and its absence results in the lack of growth and the produc- 
tion of cretinism. Almost all the cretinoid dwarfs have total absence 
of the thyroid, and in those whose thyroids appear to be normal, or 
who have a goitre, the secretion is always deficient. In later life it 
seems to be required for the development of the finer tissues, such as 
those of the nervous system. 
Our knowledge of the suprarenal bodies is rather more limited. 
Physiologically, we know that an extract can be obtained from it that 
acts strongly on the muscular tissue generally, but especially on that 
of the heart and the blood-vessels. As the therapeutic agent this quality 
has been utilized and as adrenalin it is extensively used, both surgi- 
cally and medically, to stop and prevent hemorrhage and as an adjunct 
in the treatment of shock to close the smaller blood-vessels and raise 
the general blood-pressure. Langley has shown that its effects are 
identical with those produced by stimulating one or other sympathetic 
nerve, and has suggested that its internal secretion may be the con- 
trolling agent of the sympathetic nervous system. Disease of these 
suprarenal glands (tuberculosis) is responsible for Addison’s disease, 
characterized by gradual and progressive muscular weakness, anaemia, 
gradual exhaustion, and death. In the majority of cases it is asso- 
ciated with a brown pigmentation of the skin. Experimentally, in dogs 
and rabbits it has been found that the removal of both glands is in- 
variably followed by death, preceded by symptoms closely resembling 
those of Addison’s disease. 
The pituitary body has been especially studied in connection with the 
disease known as acromegaly. This is characterized by an increase in 
size of the bones of the face, hands, and feet. In addition, the lips 
become thick and the hair and skin coarse, and the patient eventually 
becomes lethargic, reminding one somewhat of myxceddma. In all cases 
the pituitary body has been found affected, in some instances being the 
seat of a tumor. 
This disease has been ascribed to the absence of an internal secre- 
tion. It has been found experimentally that injection of an extract of 
the pituitary body causes contraction of muscle like suprarenal extract. 
Just what effect this body has on animal life, we can not tell. There 
