The passage of the borrower
imposes liability for a broken limb and natural death – which are
unavoidable mishaps. It is silent, however, about theft and loss, which
are avoidable mishaps.
We can derive it ourselves with an a fortiori argument:
if a paid custodian, who is exempted from liability when the animal
suffers a broken limb or dies, is nonetheless liable in cases of theft
and loss, is it not logical that a borrower, who is indeed liable in
cases of the animal suffering a broken limb or dying, is also liable in
cases of theft and loss? Surely this is so. 