the Prophet (sws) has directed the Muslims to burry their dead as soon as it
is possible for them. When the Almighty has ordained death for a person and
decided that he should no longer remain in this world then it is only proper
to show haste in submitting to His will by consigning the dead person to the
grave as soon as possible. Besides, needless delays in burials cause tension
and difficulty for the family of the deceased.
person's dead body after his death whether for educational purposes or for
humanitarian purposes (eg organ donation) is alright if the said person in his
own lifetime has willed it so. It is not proper to use the dead bodies which
are left uncollected from the mortuary, as, I believe, is generally the case.
Some missionary doctors should come forward to serve the cause of medical
education and donate their bodies for these purposes.