In  the  light  of  these  experiments  it  is  probable  that  the  difference  in
the  effects  produced  on  body  temperature  by  section  of  the  cervical
spinal  cord  in  man  and  the  lower  animals  depends  on  the  relative  im-
portance of  the  heat-producing  and  heat-dissipating  mechanisms.  When
the  control  of  heat  loss  is  paralyzed  in  the  smaller  animals,  the  cooling
of  the  body  becomes  excessive  in  relation  to  the  amount  of  heat  produced
in  the  paralyzed  muscles,  because  the  body  surface  is  extensive  in  com-
parison with  the  body  weight  (see  page  551).  In  the  larger  animals  such
as  man,  on  the  other  hand,  the  cooling  effect  is  much  less  marked,  espe-
cially when,  as  is  common  after  such  an  accident,  the  patient  is  kept
unusually  warm.
CONTROL  OF  BODY  TEMPERATURE  AND  FEVER  721

FEVER

The  clinical  application  of  a  Knowledge  of  the  mechanism  of  heat  regu-
lation in  the  animal  body  concerns  the  causes  of  fever.  In  the  most
familiar  form  fever  is  produced  by  infectious  processes,  but  it  may  also
be  owing  to  various  other  causes,  among  which  may  be  mentioned  the
parenteral  injection  of  foreign  protein,  excessive  destruction  of  protein
substances  in  the  body  itself,  the  action  of  certain  drugs,  and  lastly,
injury  to  the  base  of  the  brain  or  lesions  of  the  upper  levels  of  the  spinal
cord.  Various  types  of  fever  are  recognized:  when  the  temperature  re-
mains constantly  above  the  normal,  it  is  known  as  continuous  fever;
when  oscillations  occur  but  the  temperature  never  falls  to  the  normal
level,  it  is  known  as  remittent;  when  it  attains  the  normal  level  at  cer-
tain periods  during  the  day,  it  is  known  as  intermittent.
