other　from　the　idea　of　public　right。　They　are：　I。　The　contract　of
  donation　（pactum　donationis）；　II。　The　contract　of　loan　（commodatum）；
  III。　The　action　of　real　revindication　（vindicatio）；　and　IV。
  Guarantee　by　oath　（juramentum）。
  It　is　a　common　error　on　the　part　of　the　jurist　to　fall　here　into　the
  fallacy　of　begging　the　question　by　a　tacit　assumption　（vitium
  subreptionis）。　This　is　done　by　assuming　as　objective　and　absolute
  the　juridical　principle　which　a　public　court　of　justice　is　entitled
  and　even　bound　to　adopt　in　its　own　behoof；　and　only　from　the
  subjective　purpose　of　qualifying　itself　to　decide　and　judge　upon　all
  the　rights　pertaining　to　individuals。　It　is　therefore　of　no　small
  importance　to　make　this　specific　difference　intelligible；　and　to
  draw　attention　to　it。
  37。　I。　The　Contract　of　Donation。
  （Pactum　Donationis）。
  The　contract　of　donation　signifies　the　gratuitous　alienation
  （gratis）　of　a　thing　or　right　that　is　mine。　It　involves　a　relation
  between　me　as　the　donor　（donans）；　and　another　person　as　the　donatory
  （donatarius）；　in　accordance　with　the　principle　of　private　right；　by
  which　what　is　mine　is　transferred　to　the　latter；　on　his　acceptance
  of　it；　as　a　gift　（donum）。　However；　it　is　not　to　be　presumed　that　I
  have　voluntarily　bound　myself　thereby　so　as　to　be　compelled　to　keep　my
  promise；　and　that　I　have　thus　given　away　my　freedom　gratuitously；　and；
  as　it　were；　to　that　extent　thrown　myself　away。　Nemo　suum　jactare
  praesumitur。　But　this　is　what　would　happen；　under　such
  circumstances；　according　to　the　principle　of　right　in　the　civil　state；
  for　in　this　sphere　the　donatory　can　compel　me；　under　certain
  conditions；　to　perform　my　promise。　If；　then；　the　case　comes　before　a
  court；　according　to　the　conditions　of　public　right；　it　must　either
  be　presumed　that　the　donor　has　consented　to　such　compulsion；　or　the
  court　would　give　no　regard；　in　the　sentence；　to　the　consideration　as
  to　whether　he　intended　to　reserve　the　right　to　resile　from　his　promise
  or　not；　but　would　only　refer　to　what　is　certain；　namely；　the　condition
  of　the　promise　and　the　acceptance　of　the　donatory。　Although　the
  promiser；　therefore；　thought…　as　may　easily　be　supposed…　that　he　could
  not　be　bound　by　his　promise　in　any　case；　if　he　〃rued〃　it　before　it　was
  actually　carried　out；　yet　the　court　assumes　that　he　ought　expressly　to
  have　reserved　this　condition　if　such　was　his　mind；　and　if　he　did　not
  make　such　an　express　reservation；　it　will　be　held　that　he　can　be
  compelled　to　implement　his　promise。　And　this　principle　is　assumed　by
  the　court；　because　the　administration　of　justice　would　otherwise　be
  endlessly　impeded；　or　even　made　entirely　impossible。
  38。　II。　The　Contract　of　Loan。　（Commodatum）。
  In　the　contract　of　commodate…loan　（commodatum）　I　give　some　one　the
  gratuitous　use　of　something　that　is　mine。　If　it　is　a　thing　that　is
  given　on　loan；　the　contracting　parties　agree　that　the　borrower　will
  restore　the　very　same　thing　to　the　power　of　the　lender；　But　the
  receiver　of　the　loan　（commodatarius）　cannot；　at　the　same　time；
  assume　that　the　owner　of　the　thing　lent　（commodans）　will　take　upon
  himself　all　risk　（casus）　of　any　possible　loss　of　it；　or　of　its
  useful　quality；　that　may　arise　from　having　given　it　into　the
  possession　of　the　receiver。　For　it　is　not　to　be　understood　of　itself
  that　the　owner；　besides　the　use　of　the　thing；　which　he　has　granted
  to　the　receiver；　and　the　detriment　that　is　inseparable　from　such
  use；　also　gives　a　guarantee　or　warrandice　against　all　damage　that
  may　arise　from　such　use。　On　the　contrary；　a　special　accessory　contract
  would　have　to　be　entered　into　for　this　purpose。　The　only　question；
  then；　that　can　be　raised　is　this：　〃Is　it　incumbent　on　the　lender　or
  the　borrower　to　add　expressly　the　condition　of　undertaking　the　risk
  that　may　accrue　to　the　thing　lent；　or；　if　this　is　not　done；　which　of
  the　parties　is　to　be　presumed　to　have　consented　and　agreed　to
  guarantee　the　property　of　the　lender；　up　to　restoration　of　the　very
  same　thing　or　its　equivalent？〃　Certainly　not　the　lender；　because　it
  cannot　be　presumed　that　he　has　gratuitously　agreed　to　give　more　than
  the　mere　use　of　the　thing；　so　that　he　cannot　be　supposed　to　have
  also　undertaken　the　risk　of　loss　of　his　property。　But　this　may　be
  assumed　on　the　side　of　the　borrower；　because　he　thereby　undertakes　and
  performs　nothing　more　than　what　is　implied　in　the　contract。
  For　example；　I　enter　a　house；　when　overtaken　by　a　shower　of　rain；
  and　ask　the　loan　of　a　cloak。　But　through　accidental　contact　with
  colouring　matter；　it　becomes　entirely　spoiled　while　in　my
  possession；　or　on　entering　another　house；　I　lay　it　aside　and　it　is
  stolen。　Under　such　circumstances；　everybody　would　think　it　absurd
  for　me　to　assert　that　I　had　no　further　concern　with　the　cloak　but　to
  return　it　as　it　was；　or；　in　the　latter　case；　only　to　mention　the
  fact　of　the　theft；　and　that；　in　any　case；　anything　more　required　would
  be　but　an　act　of　courtesy　in　expressing　sympathy　with　the　owner　on
  account　of　his　loss；　seeing　he　can　claim　nothing　on　the　ground　of
  right。　It　would　be　otherwise；　however；　if；　on　asking　the　use　of　an
  article；　I　discharged　myself　beforehand　from　all　responsibility；　in
  case　of　its　coming　to　grief　while　in　my　hands；　on　the　ground　of　my
  being　poor　and　unable　to　compensate　any　incidental　loss。　No　one
  could　find　such　a　condition　superfluous　or　ludicrous；　unless　the
  borrower　were；　in　fact；　known　to　be　a　well…to…do　and　well…disposed
  man；　because　in　such　a　case　it　would　almost　be　an　insult　not　to　act　on
  the　presumption　of　generous　compensation　for　any　loss　sustained。
  Now　by　the　very　nature　of　this　contract；　the　possible　damage　（casus）
  which　the　thing　lent　may　undergo　cannot　be　exactly　determined　in　any
  agreement。　Commodate　is　therefore　an　uncertain　contract　（pactum
  incertum）；　because　the　consent　can　only　be　so　far　presumed。　The
  judgement；　in　any　case；　deciding　upon　whom　the　incidence　of　any　loss
  must　fall；　cannot　therefore　be　determined　from　the　conditions　of　the
  contract　in　itself；　but　only　by　the　principle　of　the　court　before
  which　it　comes；　and　which　can　only　consider　what　is　certain　in　the
  contract；　and　the　only　thing　certain　is　always　the　fact　as　to　the
  possession　of　the　thing　as　property。　Hence　the　judgement　passed　in　the
  state　of　nature　will　be　different　from　that　given　by　a　court　of
  justice　in　the　civil　state。　The　judgement　from　the　standpoint　of
  natural　right　will　be　determined　by　regard　to　the　inner　rational
  quality　of　the　thing；　and　will　run　thus：　〃Loss　arising　from　damage
  accruing　to　a　thing　lent　falls　upon　the　borrower〃　（casum　sentit
  commodatarius）；　whereas　the　sentence　of　a　court　of　justice　in　the
  civil　state　will　run　thus：　〃The　loss　falls　upon　the　lender〃　（casum
  sentit　dominus）。　The　latter　judgement　turns　out　differently　from　the
  former　as　the　sentence　of　the　mere　sound　reason；　because　a　public
  judge　cannot　found　upon　presumptions　as　to　what　either　party　may
  have　thought；　and　thus　the　one　who　has　not　obtained　release　from　all
  loss　in　the　thing；　by　a　special　accessory　contract；　must　bear　the
  loss。　Hence　the　difference　between　the　judgement　as　the　court　must
  deliver　it　and　the　form　in　which　each　individual　is　entitled　to　hold
  it　for　himself；　by　his　private　reason；　is　a　matter　of　importance；
  and　is　not　to　be　overlooked　in　the　consideration　of　juridical
  judgements。
  39。　III。　The　Revindication　of　what　has　been　Lost。
  （Vindicatio）。
  It　is　clear　from　what　has　been　already　said　that　a　thing　of　mine
  which　continues　to　exist　remains　mine；　although　I　may　not　be　in
  continuous　occupation　of　it；　and　that　it　does　not　cease　to　be　mine
  without　a　juridical　act　of　dereliction　or　alienation。　Further；　it　is
  evident　that　a　right　in　this　thing　（jus　reale）　belongs　in
  consequence　to　me　（jus　personale）；　against　every　holder　of　it；　and　not
  merely　against　some　particular　person。　But　the　question　now　arises
  as　to　whether　this　right　must　be　regarded　by　every　other　person　as　a
  continuous　right　of　property　per　se；　if　I　have　not　in　any　way
  renounced　it；　although　the　thing　is　in　the　possession　of　another。
  A　thing　may　be　lost　（res　amissa）　and　thus　come　into　other　hands　in
  an　honourable　bona　fide　way　as　a　supposed　〃find〃；　or　it　may　come　to　me
  by　formal　transfer　on　the　part　of　one　who　is　in　possession　of　it；
  and　who　professes　to　be　its　owner；　although　he　is　not　so。　Taking　the
  latter　case；　the　question　arises　whether；　since　I　cannot　acquire　a
  thing　from　one　who　is　not　its　owner　（a　non　domino）；　I　am　excluded　by
  the　fact　from　all　right　in　the　thing　itself；　and　have　merely　a
  personal　right　against　a　wrongful　possessor？　This　is　manifestly　so；　if
  the　acquisition　is　judged　purely　according　to　its　inner　justifying
  grounds　and　viewed　according　to　the　state　of　nature；　and　not　according
  to　the　convenience　of　a　court　of　justice。
  For　everything　alienable　must　be　capable　of　being　acquired　by