About  fifteen  seconds  after  the  beginning  of  the  stimulation,  the  on-
cometer tracing  of  the  right  kidney  exhibits  a  sudden  decline  which,  in
some  cases,  merely  attains  the  level  of  the  record  previous  to  the  stimu-
lation and,  in  others,  reaches  much  below  this  line.  The  left  kidney
retains  ita  small  volume  during  this  period,  or  if  a  relaxation  of  its  blood
vessete  has  already  set  in,  a  secondary  decline  may  result.  As  this
belated  decrease  in  the  volume  of  the  kidneys  occurs  synchronously
with  the  second  elevation  in  the  curve  of  the  systemic  blood  pressure,
it  must  be  ascribed  to  the  action  of  the  adrenalin  which  has  been  Hl>-
erated  by  the  left  adrenal  body  in  consequence  of  the  excitation  of  its
secretory  nerve.  Obviously,  the  severity  ofthis  indirect  vasoconstrie-
tion  of  the  renal  blood  vessels  must  be  in  complete  agreement  with  the
secretory  activity  of  the  gland.  Late  in  the  course  of  an  experiment
of  this  kind,  and  especially  if  the  stimulations  have  been  repeated  too
frequently,  the  decreate  in  the  volume  of  the  right  organ  becomes  less
abrupt  and  may  eventually  disappear  altogether.  It  need  scarcely  be
mentioned  that  the  second  summit  may  also  be  destroyed  at  any  time
by  temporarily  obstructing  the  suprarenal  vein.  The  voliune  carve
of  the  right  kidney  pursues  under  this  condition  a  course  parallel  to
the  record  of  the  systemic  blood  pressure.
