*TT] 
T. 
'S  RURAL  NEW-YORKER. 
boil  briskly  iivo  minnt08;  skim  carefully  any 
scum  that  may  rise.  It  should  bo  a  smooth 
paste.  Tut  up  in  jelly  glasses ;  lay  soft  paper 
o\er  the  raarmaJade,  and  seal  up. 
Steed  PiekU’il.  Pcartt. — To  seven  pounds  of 
fruit,  make  a  sirup  of  fom'  pounds  of  sugar  and 
one  iiuai-t  of  vinegar  ;  peolthe  pears,  cut  out  the 
calyx,  and  stick  ok>vca  into  them,  say  half  an 
inch  apart;  boil  tho  pears  in  the  siiup  until  ten¬ 
der  :  tiko  them  out  and  drain  cn  a  sieve  ;  when 
cool,  place  in  jars ;  boil  tho  sirup  liftocn  or 
twenty  minutes  longer,  then  pour  over  tho  fruit ; 
when  cold,  fasten  thick  paper  over  tiie  top. 
Bins.  llrsTic, 
Recipe  for  Canning  Pumpkins  ll’untf  d.— Eds. 
Ecual  :  "Will  some  of  your  lady  readers  of  tho 
Domestic  department  give  me  a  recipe  for  can¬ 
ning  ])umpkiu  so  it  will  be  fresh  in  tho  winter  or 
spring  BIii.s.  E.  J.  W. 
[Will  some  of  oim  lady  readers  respond  and 
oblige.— Ed.J 
To  *•  .Didi.’' — To  drive  away  ants — black  or 
red— I  sprinkle  fine  salt  all  over  tho  [miitry 
shelves,  also  occasionally  wash  thorn  out  witii 
hot  salt  water.  Tlicy  hate  salt  as  much  iw  they 
love  sugar.  I  have  heard  that  tobacco  <lust  is 
also  very  good  for  thl.s  p\u'poso. 
A  wot  sponge,  sugared,  will  collect  them,  then 
throw  it  in  hot  water, — o.  n.  c. 
Anotlwr. — .My  remedy  for  that  pest,  tho  “red 
ant,"  is  kerosene.  If  they  go  in  tho  cupboaid,  I 
rub  it  on  tho  shelves,  in  a  fow  days  tlicy  will  bo 
gone,  then  you  can  wash  up  with  hot  soap-suds. 
You  can  rub  kerosene  on  tho  outside  of  barrels  or 
largo  jars.  I,  for  one,  think  kerosene  can  be 
tolerated  better  than  “red  ants.”-  5ln.s.  11.  II. 
Andkkws. 
C'.  >• 
0 
a 
cS!' 
MALARIA.' 
Tho  terms  malaria  and  miasm  hi  medicine  hi- 
clude  the  causes  of  a  largo  class  of  affections— 
what  .arc  known  more  particularly  as  zymotic 
diseases,  which  depend  ujion  a  variety  of  specific 
orgauic.  jK)i-;on«  whoso  osseudal  nature,  coiupo- 
Bilion,  and  form,  lu-o  mostly  iuajiprcciable  as  yet 
by  Bciontiih-  research.  The  general  understand¬ 
ing,  however,  of  tlie.'io  terms,  is  more  limiti  d ; 
and,  ill  conformity  with  the  popular  idea,  I  shall 
in  tho  present  p.apor  confino  then-  application  to 
tho  cause  of  tlioso  wide-spread  disorders,  hUer- 
milhnl  uikI  remUtrnt  fevers— tho  formor  of 
which  is  .so  well  known  as  “  chills  and  fever  “  or 
“  fever  and  iiguo.  ’ 
“Time  out  of  mind,”  as  Watson  remarks, 
“it  had  been  matter  of  common  observation 
that  tlic  inhabitants  of  wet  and  marshy  sitiia- 
llons  were  o.specially  subject  to  those  detinite 
and  umquivocai  forms  of  disease.”  The  same 
iintiiral  iigencies  which  are  now  at  work  elabor¬ 
ating.  evolving,  and  dLsseminatiiig  malaria  must 
liavo  been  otpially  in  operation  ever  siiico  tho 
surface  of  the  earth  assumed  its  present  con¬ 
dition.  Vast  and  remote  wildernosses  that  have 
never  known  Iiiimau  presence  teem,  as  of  yore, 
with  deadly  exiialations  that  almost  preclude  the 
hnkl  attempts  of  eutorprising  man  to  lay  bare 
their  secrets.  There  lu-e  aomo  parts  of  India,  as 
Bishop  Heher  informs  us,  which  even  monkeys 
aud  other  wild  animals  iustinctively  dusoVt 
between  April  and  October  of  eacli  year.  The 
tigers  go  up  to  tlio  LLIls ;  the  antolojKiS  aud 
wild-hogs  luako  meursious  into  tlio  cultivated 
pJaiiia ;  and  tlioso  persons,  such  as  dak-hearers 
and  milit.'uy  people,  who  are  obhged  to  venture 
into  the  marshy  jungles,  agi-ee  that  not  so  much 
as  a  bird  can  bo  heard  or  seen  in  tho  friglitful 
solitude. 
Taking  tho  United  States  census  of  1870  as  a 
guide  for  our  own  country,  wo  find  malarial 
ftver.5  forming  »,  \cry  important  foatm-o  of  tlie 
mortality-taWe.s.  They  ai-e  most  fatal  in  Elorida, 
Louisiana  and  Tc.xas.  Next  in  order  follow 
Arkansas,  Mi.s.sissippi,  Alabama,  (Icorgia,  Mis¬ 
souri,  Kansas  aiul  Nevada.  In  another  group 
(hitinguished  by  a  somewhat  Ic.ss  mortality  wo 
find  Now  BIo.xico,  tho  Caroliiias,  Virghda,  Toii- 
nosseo,  Kentucky,  lUinols,  and  ImUana.  Those 
States  marked  by  the  lowest  niorlulity  arc  tlie 
New  England  and  Bliddle  States,  Wisconsin,  and 
Minnesota.  In  Califoi'nia  tliore  is  a  considerable 
ratio  of  mortality,  diminishing  easterly  in  Utali. 
and  uortlieriy  in  Oregon  and  Washington  Terri¬ 
tory,  while  it  augments  largely  toward  tho  soutii 
in  New  M(,‘xico.  Sinco  tho  census  was  taken, 
however,  that  is,  since  about  1869,  there  has 
been  noticed  an  evident  extension  of  tho  subtile 
niiA.siaatic  .agency  over  regions  previously  ex¬ 
empt  from  it,  in  the  Middle  and  New  England 
oUtos.  Tho  increase  of  mortality  by  this  cause 
m  New  York  City  has  Leon  notable,  but  can 
scarcely  be  attributed  entirely  to  local  influences.  | 
1  .u  ^  registered  in  tliis  city  only  98 
deaths  from  malarial  fevers.  In  1869  they  ro.se  ' 
^2^8 ;  in  1870,  to  ms ;  in  1871,  to  291 ;  and  in 
before  the  Now  York 
1372,  to  3  IS ;  un  increase  of  850  per  cent,  in  four 
years.  Since  then  some  diminution  in  thoir 
fatality  has  occurred.  Thev  occasioned  282 
!  deaths  in  1873,  29,'>  in  187-1,  and  275  in  1875. 
Let  us  now  consider  under  what  circumstances 
nuilari.a  may  be  produced.  Although  it  cannot 
ho  denied  that  tliore  aro  peculiar  localities  where, 
with  apparently  every  presumed  condition  oxist- 
ing  for  tho  <leveIopmcnt  of  malaria,  tliat  poison 
is  entirely  absent,  yet  tho  concurrence  of  malar¬ 
ial  euinaatioiKs  wifJi  such  conditions  in  iunumor- 
ablo  placo.i  ostabliHlios  beyond  a  question  their 
dii'ciit  relation.  Tho  essential  clement  in  the 
production  of  malaria  would  appear  to  bo  vege¬ 
table.  decomposition;  and,  in  order  that  this 
process  shall  ensue,  tlio  simultaneous  operation 
of  air,  nwisturc,  and  a  certain  high  range  of 
lemp,rature,  is  .absolutely  roquirod.  ’  Localities, 
tlicreforo,  whero  such  combiuaUon  occiu-a,  aro 
proUllo  of  malaria.  0  f  this  character  aro  swamps 
and  morasses,  alluvial  deposits,  loose,  porous, 
•sandy,  and  argiUaceous  soils,  or  deep,  loamy! 
marly  lands  underlaid  by  impermeable  strata 
afforditig  capacity  for  tbe  rctoutiou  of  moisture, 
regions  exposed  to  periodical  or  occasional  inun¬ 
dation,  jilaces  left,  bai'o  by  the  subsidence  of 
lakes  or  drying  up  of  streams,  and  particuJarly 
areas  subject  to  (bo  interiuingliug  of  salt  and 
fresh  water— as  .salt-marfihoa  into  which  fresh 
stroams  discharge,  or  regions  liable  to  tidal  over¬ 
flow  and  recession. 
The  e.xhalarious  fiom  manshy  tracts  arc  recog¬ 
nized  by  their  effects  upon  tlie  human  system 
tiu’oughout  tho  world  ;  and  tho  fact  that  marshes 
hear  a  causativo  relation  to  malaria  has  Leon  de¬ 
monstrated  ill  iinraorons  instanocs  by  the  disap- 
iwaranco  of  fever  after  thorough  ilrainago  aud 
cuUiv.ation,  and  its  roapiiearanoo  uiwm  their 
being  allow'cd  to  relapse  mto  neglect.  Tho 
favonahlo  effect  of  drainage  and  cultivation  is 
owiug  both  to  tbe  systematic  removal  of  water 
near  the  surface,  and  most  probably  also  to  tho 
absorption  by  tlic  growing  crops  of  the  products 
of  organic  doeoinnoBition.  On  tho  same  principle 
ITof.  Maury  succeeded  in  autagonizing  the  nox¬ 
ious  oin.-vnations  from  a  tnarBli  surrounding  tlio 
ob.scrvnkuy  at  Waslungtou  by  planting  it  thickly 
with  sunflowers,  'vhich  seem  to  ixisscss  an  extra¬ 
ordinary  absorbing  power,  yobastian  is  inclined 
t<i  believe  tliat  tlic  Calatosis  aromaiictis  which 
grows  in  somo  swamps  has  a  Himilar  neutralizing 
quality,  y  wamps  covered  witli  water  aro  not  so 
dangoroiH  as  those  partially  dry,  the  Layer  of 
water  serving  as  a  protection  against  tho  access 
of  air  and  heat  to  the  vegetablo  matter  under¬ 
neath. 
A  certain  continuous  range  of  tcmiioraturo 
seems  essonlial  to  tlio  development  of  maJai’i,a, 
wliicli  i.s  almost  uuluiown  beyond  60''  north  and 
57*^  south  l.atitudo,  aud  during  the  cold  season  In 
Uic  tomiieriito  zone.  [Thoro  aro  localities  whore 
iutcrmittiiig  fevers  aro  oven  more  common  in 
winter  than  in  summer  in  tho  temperate  zone.— 
Edh.  |  According  to  llirscli,  it  jirovaiJa  up  to 
Vuriious  degrees  of  latitude  aud  average  annual 
tomperaturo.  It  is  tlio  average  summer  tem- 
peratm-o,  however,  that  is  of  account,  aud  the 
northern  limit  of  lliis  lies  lietwceu  ttio  isotherms 
of  59  '  .and  50.8  Eahr..  giving  a  prolonged  tom¬ 
peraturo  siUiiciently  liigli  to  insure  vegetable  dc- 
compo.'<ition. 
I  ho  alluvial  soil  along  tho  banks  of  rivers  and 
at  their  delta.s,  as  those  of  the  Gauges,  Nile, 
Orinoco,  and  BliHsiBsippi,  gives  rise  to  fevers  of 
a  very  malignant  tyiio.  Them  banka  are  subject 
to  overflow,  and  frequently  have  a  clayey  sub¬ 
soil,  presenting  an  obstacle  to  percolation — thus 
upon  the  river  s  recedhig  into  its  ordinary  chan¬ 
nel  its  baut.s  reinaiu  damp  below  the  surface, 
and  diHcai-e  is  generated  by  tJie  sun’s  agency! 
A.  like  process  aminally  takes  place  in  the  exton- 
siM)  plains  and  table-lands  formed  of  alluvium 
AMislieil  down  from  nioun tain-ranges  diuaug  tho 
lapse  of  centoi-ioH,  and  having  few  actual 
marshes.  I’rofuso  rains,  succeeded  by  dry  hot 
seasouB,  render  sucli  regions  exceedingly  insalu¬ 
brious  during  certain  periods  of  the  year. 
Somewhat  similar  in  character  aro  the  oases  of 
the  Desert  of  Sahara,  which  aboiind  in  malaria, 
ifii'sch  describes  these  spots  as  coii^sting  of 
trough-liko  dojiressions  iu  a  rocky  or  hlghly- 
hygroscopic  soil,  tho  receptacle  of  subterranean 
waters,  and  covered  with  a  layer  of  alluvium, 
the  sm-/aco  of  the  oasis.  In  thi.i  the  tierce  heat 
of  tho  sun  causes  cracks  and  deep  rifts  in  the 
earth,  which  give  free  vent  to  the  miasm  evolved 
from  beneath. 
JjOCttlitioB  sub  ject  to  tlio  intermixture  of  salt 
and  iretih  ivater  arc  particularly  prone  to  malaria. 
IhcMarcnimas  of  Italy  afford  examples  of  this 
oil  a  large  scale.  The  Marcmma  of  Lucca  con- 
si.sts  of  three  basius  formerly  dotted  over  with 
ponds  and  pools.  It  had  boon  for  centuries  fre¬ 
quently  overflowed  by  the  se.vtides  which  iutcr- 
mingled  with  its  fresh  ponds.  Malaiiiil  fevers 
ravaged  it  aud  rendered  it  almost  nniuhabitable. 
To  tho  wayfarer  wlio  wa.s  so  imprudent  as  to 
spend  a  night  of  August  or  September  within  its 
desolate  hounds,  the  penalty  was  almost  certain 
death.  A  remedy  for  tin's  deplorable  condition 
of  things  was  long  sought-  A  i>roi)osition  had 
been  made  in  1714  by  the  engineer  liondelli  to 
attempt  the  exclusion  of  tho  sea.  Renewed  in 
1730  by  Manfredi,  aud  six  years  later  by  Zcndiiiii, 
a  mathematician  of  Bologna,  tho  idea  was  finally 
canied  into  execution  in  1740.  Tho  initial 
attempt  was  made  upon  tho  piincipal  aud  most 
imhealthful  basin.  A  aluieo  was  construoteil  at 
the  entrance  of  tho  caual  of  Burlamacca  through 
which  tho  waters  of  the  sea  penetrated  into  tho 
basin  to  its  central  pond.  Tho  llood-gate  was  so 
arranged  as  to  act  like  a  valve,  shutting  by  the 
pressmo  of  tho  risiug  tide  .and  opening  when  it 
fell.  The  success  of  this  outorpriso  was  so  com¬ 
plete  that  in  the  following  year  tho  miasmatic 
diseases  which  bail  never  failed  to  shoiv  them¬ 
selves  annually  tUd  not  reappear,  and  tho  whole 
district  Avas  rendered  salubrious.  It  was  at  this 
period  that  tlio  village  of  Viarregio,  previously 
abandoned  and  composed  only  of  a  few  fishers’ 
lints  grouped  at  the  foot  of  au  old  toAver  where 
galloy-slavos  wero  contiuod,  became  a  place  of 
fashionable  resort  during  tho  simimor  for  the 
aristocracy  of  Lucca.  This  fact  of  a  region’s 
being  rendered  healthy  by  the  exclusion  of  sea- 
wator  is  curious,  but  made  more  decisive  ittill  by 
its  coimter-proof.  Iu  17C8-’69  fovors  suddenly 
sprang  np  again  as  bad  as  over  in  tho  samo  torri- 
toiy.  Upon  tho  canso  being  investigated,  it  Avas 
foimd  that  tho  sluice  had  becoino  deranged  and 
tiie  mixture  of  Avaters  Jiad  boiAii  re-established. 
Upon  the  llood-gate  lieing  rop.-ur«d,  tho  malaria 
Avas  again  extinguished.  The  Kamo  occurrence 
happened  in  1784-'8S.  The  sluice  Imvirig  been 
neglected,  thoro  took  place  in  1781,  out  of  a  pop- 
Illation  of  1,990,  tho  euormons  number  of  1,200 
cases  of  jualai’ial  fever  and  92  deaths.  In'tlie 
folloAViug  year  there  occurred  lO.'i  deaths.  Tlio 
trouble  Avas  romedksl  in  the  sauio  manner  as  be¬ 
fore.  Tho  other  iiorlions  of  tlio  .Maromma  woro 
rendered  healthy  later,  by  sluices  successively 
ostahlishcd  at  di/Tereut  points.  Bach  a  romai  k- 
ablo  result  ueceHsarily  atti-aoted  public  attention. 
Leopold  11.,  Graud-dnko  of  Tuscany,  was  par¬ 
ticularly  impressed  by  it,  and  ho  conocivod  the 
groat  Idea  of  improving  tlio  whole  Tuscan 
Mariiuima  in  tlio  sarao  manlier,  ft  AA'as  au  itu- 
mense  undertaking  which  lie  contemplated  an 
actual  transfomatioii  of  a  largo  jiart  of  his 
dorahilous— and  it  redounds  to  his  glory  that  lie 
succeeded,  in  tho  taco  of  almost  inaurniountahlo 
ohstiMdoB,  by  Uni  means  doseribod,  and  a  proper- 
ly-dircctcd  system  of  canalization  and  fleld- 
eulturo,  in  regenerating  a  very  considerable  por¬ 
tion  of  his  territory. 
It  is  not  ditlicult  to  account  for  tho  generation 
of  malaria  under  such  oircimistaiicoa  as  those 
just  moutioned.  The  inliiuto  forms  of  vegetable 
life  witli  Avhioh  both  fresh  aud  salt  water  teem 
require  their  own  special  element  for  oontinuod 
oxlstence.  The  inteniuktm’o  of  salt  with  fresh 
Avator  introduces  a  now  clement  with  which  Uio 
life  maiiitaiiiodineaeh  separately  is  incompatible. 
I’he  Rurfaco  of  tho  soil  consequrmtly  after  every 
invasion  and  retirement  of  tho  tide  exposes  to 
the  action  of  tho  heat  a  mass  of  dcfiiuot  vogotablo 
material  spread  out  over  an  extensive  area,  and 
in  most  favorable  condition  for  speedy  decompo¬ 
sition. 
Besides  tho  localiUos  enumerated,  malaria  is 
apt  to  be  iudiioed  or  iuten.slflcd  hi  a  region  whol¬ 
ly  or  comiiarativoly  exempt  from  it  before,  dur¬ 
ing  Uio  distnrliance  of  largo  extents  of  soil,  as  in 
tho  coustniotiou  of  canals,  road.s,  railways,  forti¬ 
fications  and  dilics,  rooting  out  of  timber,  prepa¬ 
ration  of  virgin  land  for  cultivaUon,  etc.’  Vege¬ 
table  organi.sius  previously  hidden  and  protected 
undorgi-omid  are  thus  brought  to  the  surface 
and  exposed  to  tho  agoucios  of  putrefaction. 
Laborers  engaged  in  such  Avorks  and  tho  neigh! 
boring  inhabitants  soon  suffer.  The  “  polders  ” 
of  Hollaua,  those  parts  roclaimcHl  from  the  sea  by 
the  erection  of  dikes,  are  of  this  character,  and 
the  workmen  engaged  on  thorn  lu-o  attacked  Avith 
malarial  troubles  of  great  severity.  In  this 
country  such  instances  aro  common.  Wo  have 
an  example  at  om’  very  doors  in  the  Iiicreaso  of 
malarial  fevers  Avhieh  accompanied  the  openuig 
of  the  iicAV  boulevards,  and  the  ODgiueoring  ox- 
cavatlous  of  the  Ilarlom  Railroad.  After  .such 
Avorlis  have  been  completed,  however,  it  is  not 
unusual  for  the  viuhiity  to  he  restored  to  health- 
fulucBS. 
It  must  he  acknoAvledgotl  tliat  occaeionally 
miasmatic  fevers  appear  and  disappear  without 
Uicro  having  occurred  any  pcrceiitiblechuugos  in 
tho  relations  of  tho  soil.  Hiich  circuniBtances 
wero  reported  to  tho  Pennsylvania  State  Alcdieal 
Society  as  haAflug  been  noticed  in  along  tlic 
Juniata  River.  Reports  to  the  Oonncotlout 
State  MeiUcal  Society  atso  mention  tlio  appoar- 
anco  of  miasmatic  disorders  withont  any  recog¬ 
nized  cause  in  portions  of  the  Btate  previously 
exempt  from  them. 
Au  impeded  outfloAV  which  raises  the  level  of 
the  gronnd-wator  has  been  productive  of  au  Im¬ 
mense  spread  of  paroxysmal  fevers.  Deraster, 
Taylor  and  Ferguson,  have  reported  such  to 
have  been  the  case  in  portions  of  ludw.  The 
severe  and  fatal  fevers  prevailing  in  Bmdowan, 
Lower  Bengal,  during  tho  last  flfteen  or  twenty 
years,  have  been  comcident  with  obstruction  to 
the  natural  drainage  from  mills,  and  blockage  of 
Avater-courses.  Tho  same  cause  has  doubtless  ' 
operated  to  a  great  extent  in  producing  the 
fevers  of  Bloomingdolo,  Mauliattaiiville,  York- 
villo  and  Ifarlom.  The  ostabllshmont  diuing 
the  past  IIa'o  years  of  extensive  subsoil  drains  in 
tlioso  porUoii.s  of  New  York  has  had  a  visiblo 
teiidoiioy  to  diminl.sh  tho  area  of  malaria.  A 
Himilar  result  on  a  largo  scale  has  been  noticed 
in  laucolnshiro  and  other  ports  of  England 
where  many  malarious  tracts  have  boon  rendered 
quito  healthy  liy  similar  moa.snreH,  having  for 
thoir  object  tho  lowering  of  tho  subsoil  water- 
lovel  by  an  increased  outflow. 
With  regard  to  tlie  (picstioii,  “  Can  ch-inldng- 
_  water  act  as  a  vohiolo  for  tho  hitiMduction  of 
1  malaria  into  tho  animal  system  ?”  a  priori  it 
seems  roasoiiablo  to  suppose  that  such  may  bo 
the  case.  If  malaria,  ho  it  a  gaseous  substance 
oi  an  aceuimilation  of  rainuto  organisms,  cannot 
pollute  water,  it  differs  cssontially  from  other 
materials  of  similar  form  Avith  wliich  we  aro  bet¬ 
tor  acquainted.  But,  In  fact,  wo  have  positive 
proof  tliat  malarial  fevers  mav  he  duo  to  drink¬ 
ing  impnro  water.  In  I834  thoro  roturuod  to 
MaisciUos  from  Bona  in  the  ship  Argo  120 
sokliors,  of  whom  10, J  wero  seized  Avitli  various 
forms  of  malarial  fever  after  di-inldng  marsh- 
water  taken  on  hoard  at  Bona.  On  tlio  other 
baud,  tho  sailors  of  the  same  ves.sel,  Avho  had 
puro  Avater,  and  780  iiion  embarked  on  two  other 
vessels,  renuiiticd  well,  fl’lio  few  soldiers  on  tho 
Argo  not  attacked  liad  purchaBcd  their  drinking 
Avator  from  the  sailors.  Against  sucii  positive 
CAudonco  as  tiiis  the  statement  nf  Fiuko  that  in 
Hungary  and  Holland  marsh-water  is  druulc 
AA-itliout  injury  is  of  little  value. 
Tho  Rtratimi  of  air  overlying  typical  malarial 
tnarshos  lias  been  exaniinod  with  particular 
care.  It  has  been  fouad  to  contain  an  excess  of 
carbonic  acid  watery  vapor  in  largo  quantity^ 
often  oarburotted  hydrogen,  afld  occasionally 
free  hydrogen,  ammonia,  and  phospli  iirctted 
hydrogen.  If  tbe  marsh  coiitiiiiiM  sulphates, 
sulphuretted  hydrogen  is  present.  Its  organic 
matter  blackens  sulpliiiric  acid-  gives  a  reddish 
color  to  nitrate  of  silver  -has  a  llocculont  tippoar- 
aneo,  a  peculiar  odor,  and  all'orils  ovidcnco  of 
ammonia.  Tlioao  various  oxami nations,  though 
interesting,  bring  us  no  nearer  to  a  solution  of 
the  qucHtion,  U'hal  is  tlm  naiurc  of  malaria  ? 
All  of  the  many  substaiicoa  and  forms  tlius  far 
observed  in  malarial  localities  may  bo  found 
equally  in  districis  perfectly  salubrious. 
That  it  gains  access  to  the  system  principally 
through  the  rospiratory  organs  is  quite  certain. 
Wlmt  Avo  really  do  know  of  it  lias  reference  more 
(larticularly  to  its  mode  of  action.  It  is  most 
il*ngoroua  when  tlie  aim  is  down,  and  it  seems 
almost  inert  during  (hn  tUay.  It  appears  provi¬ 
dential  tliat  tho  same  agency  which  is  so  potent 
ill  its  production  should  bo  tho  principal  instru¬ 
ment  of  its  dostriietion.  It  loves  tho  ground, 
Avhoro  in  many  regions  it  is  so  ooncontratod  and 
deadly  as  to  destroy  tho  Incautious  sleeper  on 
tho  earth  almost  as  quickly  as  tho  most  noxious 
gas.  Itonco  it  is  gonorally  regarded  as  hiiviiur  a 
Hpeciflc  gravity  lieavier  than  that  of  au-,  but  this 
IS  by  HD  moans  oertaiu.  It  Is  doubtless  rendered 
heavy  by  combining  with  night-fogs  and  dews, 
not  upon  tlieir  being  dissipated  l>y  the  suu  it 
lises  Into  the  air  and  probably  bccuUioB  innocu¬ 
ous  by  Avule  diffii-Hion  and  dilution.  It  is  inter- 
oepted  by  impcdinients,  such  as  wulls  aiul  groves 
of  leafy  trees,  wbicli  obstruct  tlie  winds  that 
boar  It.  tVrhapa  tlic  latter  also  neutralize  it  by 
almorption.  It  is  likewise  ucntralizcd  ami  i  rob- 
ably  iiiisorbod  in  passing  over  n  cousidf  rablo 
body  of  watci'— oHiiocially  salt  water.  Tho  dis¬ 
tance  necessary  to  effect  tliis  result  naturally 
varies  with  cirouinstauces'  force  of  winds  con- 
coutiatiou.  inton.sily,  and  almndanco  of  the 
poison  itself.  According  to  Blane,  In  tho  chan¬ 
nel  between  Rovoland  and  W.alchoren,  3,000  feet 
of  water  rendered  it  inert.  In  China,  three- 
qiiartors  of  a  mile,  and  in  tho  West  Indies,  one 
niilo,  have  been  roquirod  to  bo  effectual. 
Recognizing  tho  facto  mentioned,  the  precau¬ 
tions  to  ho  obsorved  against  malaria  are  quite 
obvious.  In  built-up  cities  aa'O  are  protected  by 
pavenjents  and  soavoi-s  to  a  great  ex  tout,  and 
probably  al.jo  by  tho  character  of  tlio  .atmos- 
fihcre,  which  is  artiflmlly  warmed  by  radiation 
at  night,  and  [mjircgnated  witli  gases,  which, 
though  injurious  m  other  ways,  arc  autagoiiistic 
to  malarial  euiaiiatioiis.  But  in  malarial  subur¬ 
ban  iwid  eonutry  districts  it  Is  otlienvise.  There 
certain  jirecautlous  aro  necessary.  If  possible 
olevaUon  of  a  dwelling  placa,  at  least  50(J  feet 
above  the  source  of  tho  iiuatuu,  is  to  bo  rccom- 
nieiidwliu  temperato*  climates,  and  from  1,600  to 
2,900  feet  in  tho  tropios.  if  tiiis  bo  not  pracli- 
oablo,  thorough  subsoil  draiiiago,  fllling  up  of 
low  aud  moist  grounds,  covering  the  earth  with 
closely-cul  herbage,  bolto  of  umbrageous  trees 
mterposed  between  tho  dwelling  and  the  point  of 
danger,  but  at  a  BulUciont  dwtanco  to  permit 
free  ventilation,  and  tho  acoos.H  of  sunlight; 
doors  and  Avitidows  oiienlng  principally  aivay 
from  the  malarial  quarter ;  tlio  house,  if  possible, 
to  be  raised  on  nillars  or  arches  a  fCAv  feet  above 
the  ground,  othorAvise  a  Kub-eellar  thoroughly 
cemouteil^  all  theso-aro  measures  of  primary  im¬ 
portance.  Tho  sleeping  apartmoutB  Bhould  not 
ho  lioloAV  the  eecond  story,  and  Hhould  he  pro¬ 
vided  with  open  fireplaces  iu  Avhicli  on  damp  or 
chilly  niglita  a  little  tiro  may  he  kindlod.  Ex- 
poaure  to  the  open  air  after  sunset,  or  until 
several  hours  after  sunrise,  should  bo  avoided. 
.Vs  Avhatover  tends  to  loiA'cr  tho  vital  powora  pre¬ 
disposes  the  individunl  to  malarial  invasion,  per- 
siinal  hygiene  is  indiapeiihablo.  It  Bhould  of 
course  tic  dictated  by  Common  sense,  Avith  tho 
objent  of  catablialiing  and  maintaining,  in  tho 
Avord.s  of  the  old  maxiiii  of  the  Sanitarian,  mens 
Sana  in  corpore  sano.  '.I 
