AjanS5"  ^917™'}    Notes  from  Research  Laboratory.  37 
secretion  are  infantile  cretinism,  cachexia  thyropriva  (cachexia 
strumipriva)  and  myxedema. 
These  diseases  are  characterized  chiefly  by  physical  and  mental 
inertia ;  decreased  metabolism ;  abnormal  sensations  of  taste,  smell, 
and  hearing ;  subnormal  temperature ;  slow,  weak  pulse ;  changes  in 
the  skin  (dryness,  abnormal  pigmentation),  falling  and  blanching 
of  the  hair,  and  tendency  to  obesity.  In  the  infantile  type,  physical 
and  mental  development  are  greatly  retarded  and  unless  the  thyroid 
deficiency  is  supplied  such  children  become  dwarfed  and  idiotic. 
The  metabolism  is  decreased  more  in  thyroid  diseases  than  in  any 
other  known  condition. 
In  addition  to  the  above  clear-cut  instances  of  diminished  secre- 
tion of  the  thyroid,  there  are  a  number  of  conditions  of  hypo- 
thyroidism of  less  severe  types.  Certain  cases  of  anemia,  scurvy, 
mental  disturbances ;  retarded  growth  in  children ;  fatigue  from 
slight  exertion;  tendency  to  obesity;  swelling  of  the  joints  attended 
with  feeling  of  stiffness,  dryness  of  the  skin  with  tendency  of  the 
nails  to  crack,  and  often  associated  with  caries  (decay)  of  the  teeth ; 
and  migraine — all  these  have  been  correlated  by  various  investi- 
gators with  deficient  secretion  of  the  thyroid. 
On  the  other  hand,  the  four  cardinal  symptoms  of  "  hyper  "  or 
too  copious  secretion  are,  enlargement  of  the  thyroid,  rapid  heart 
action,  nervousness,  and  exophthalmos  (protrusion  of  the  eye  balls), 
These,  with  other  secondary  symptoms  varying  in  character,  consti- 
tute the  symptom-complex  of  Graves'  disease  (exophthalmic  goiter). 
The  thyroid  enlargement,  while  one  of  the  constant  symptoms,  is 
not,  as  a  rule,  very  marked.  The  cardiac  and  nervous  symptoms 
as  well  as  the  exophthalmos  vary  with  the  degree  of  hyper-secretion. 
In  advanced  cases  of  exophthalmic  goitre  with  marked  toxemia,  the 
nervous  and  cardiac  disturbances  are  often  extremely  severe. 
In  the  treatment  of  the  three  typical  forms  of  thyroid  insuffi- 
ciency, the  use  of  thyroid  preparations  has  been  attended  with  strik- 
ingly good  results.  The  early  administration  of  thyroid  products 
in  cretinism  enables  these  children,  who  would  otherwise  be  dwarfed 
and  idiotic,  to  develop  normally,  both  physically  and  mentally.  The 
glandular  material  must,  however,  be  administered  over  a  period  of 
many  years,  often  during  the  entire  lifetime  of  the  patient.  In 
cachexia  thyropriva  and  myxedema,  results  of  treatment  are  very 
much  the  same. 
With  the  other  conditions  which  have  been  more  or  less  loosely 
