20  „

„

1  „  ai

M

2  „

10  „

»

20  „

Work  done  in

tons  lifted

Ifoot.
.    17-67
.     35-34
.  176-7
.  353-4
andcBrryin„'601bs.     24.-75
49-5
247-5
„  495


From  the  above  data  something  like  a  rough
approximation  may  be  formed  of  the  daily
amount  of  exercise  requisite  for  a  healthy
male  adult.
Since  500  tons  lifted  a  foot  is  ex-
tremely hard  work,  the  number  of  miles
corresponding  to  this  extreme  amoant  of
labour  would,  if  persevered  in,  be  objection-
able.
Dr  Parkes,  regarding  300  tons  lifted  a
foot  as  an  average  day's  work  for  a  healthy
man,  thinks  that  walking  exercise  equivalent
to  half  that  amount  should  be  taken  daily.
680


EXPANSION


U


This,  or  a  150  tons,  represents  a  nine  miles'
walk.  He,  however,  qualifies  the  suggestion
by  adding  "that,  as  there  is  much  exertion
taken  in  the  ordinary  business  of  life,  this
amount  may  be  in  many  cases  reduced ;"  and
concludes  by  saying,  "  It  is  not  possible  to  lay
down  rules  to  meet  all  cases,  but  probably
every  man  with  the  above  fucts  before  him
could  fix  tlie  amount  necessary  for  himself
with  tolerable  accuracy."

For  muscular  exercise  to  be  safe  and
efficient,  it  must  be  taken  under  certain
conditions  and  precautions.  We  have  noticei
the  evil  effects  of  immoderate  bodily  exertio|
on  the  heart.  The  lungs  are  no  less  seriousV
affected  by  an  excessive  indulgence  in  it,
which  shows  itself  in  spitting  of  blood  and  in
congestion  of  the  pulmonary  vessels.  Con-
gestion of  the  lungs  brought  on  by  over-
taxed bodily  strength  very  frequently  causes
the  death  of  horses  in  the  hunting  field.
