io  Mr.  hunter  on  the  Heat,  8 cc. 
parts:  on  the  contrary,  in  a cold  atmofphere,  a man’s 
hand  fhall  become  fo  cold  as  to  lofe  the  fenfation  of  cold 
altogether,  and  change  it  for  that  of  pain.  Real  heat 
and  cold  can  be  carried  fo  far,  as  even  to  alter  theftruc- 
ture  of  the  parts  upon  which  the  adtions  of  life  depend. 
As  animals  are  fubjedt  to  variations  in  their  degrees  of: 
heat  and  cold  from  external  applications,  they  are  of: 
courfe,  in  this  refpect,  affedted  in  fome  meafure  like  in- 
animate matter;  and  therefore,  as  parts  are  elongated  or 
recede  from  the  common  mafs,  thefe  effedts  more  rea- 
dily take  place:  for  inftance,  all  projedting  parts  and  ex- 
tremities, more  efpecially  toes,  fingers,  nofe,  ears,  combs, 
of  fowls,  particularly  of  the  cock,  are  more  readily  cooled, 
and  are  therefore  molt  fubjedfcto.be  affected  by  cold.  Ani- 
mals are  not  only  fubjedt  to  increafe  and  decreafe  of 
heat,  fimilar  to  inanimate  matter ; but  the  tranfition  from- 
the  one  to  the  other  (as  far  as  they  allow  themfelves  to 
go)  is  nearly  as  quick.  However,  I.  fhall  not  confine 
myfelf  to  fenfation  alone,  for  it  is  in  fome  degree  ruled 
by  habit  : the  habit  of  uniformity  in  the  degree  of  the, 
one  or  the  other,  will  be  the  caufe  of  a confiderable  in- 
creafe of  fenfation  from  the  fmalleft  variation while  the 
habit  of  variation  in  the  degree  of  heat  and  cold,  will,  in 
a proportional  degree,  prevent  the  fenfation  arifing  from 
either:  but  we  fhall  be  guided  by  adtual  experiment. 
2 The 
