80 THE INTERNAL SECRETIONS—1920 
munity of the animals against B. pyocyaneus. It is, 
however, well known that any operation may have the 
same influence in diminishing the natural resistance of 
the body. Sajous (2), Lorand (3), Miller (4, 5), 
Marbé (6, 7, 8, 9, 10,11), and Palazzo (12), have found 
that the thyroid gland plays an important part in im- 
munology and that removal of the thyroid in animals 
diminishes the opsonic index against microbes. 
There are, however, many authors who do not con- 
firm these views. Fassin (13, 14, 15), did not observe 
any difference in the amount of complement before and 
after thyroidectomy in animals. She stated, however, 
that experimental injections of thyroid extract or its 
oral ingestion in man increases the amount of comple- 
ment. This last statement has been confirmed by 
Miiller (5), Bianchi Mariotti (16), and Frouin (17) ; 
and Fijeldstad (18) never detected a difference be- 
tween the formation of antibodies in animals with and 
without a thyroid gland. Frouin even goes further, 
for he states that animals from whom the thyroid is 
removed, give, when immunized against tetanus, a 
much higher antitoxic serum than the normal control 
animals. Very recently these experiments have been 
repeated by Garribaldi (19, 20). He found that in rab- 
bits, which were injected with corpuscles of the sheep, 
the titration of the hemolytic antiserum was higher 
when the thyroid previously had been removed, than in 
normal animals. He also stated that the serum of 
thyroidectomized dogs had a higher amount of hetero- 
hemolysin than the serum of normal animals. 
Stepanoff (21), has proved that the resistance of thie 
body to infections is largely increased by the adminis- 
tration of thyroid extract. Parhon (22), was able to 
prove that thyroid preparations may prevent sponta- 
neous infections in birds and other animals and that 
they even may play an important part in cholera pre- 
vention in men. Koopman (23), observed two rabbits 
