Section 7-618. Chattel mortgages, etc

, and renewals thereof to be indorsed.
  When a  chattel  mortgage  or  a  conditional  bill  of  sale  or  other
  instrument  affecting  chattels is presented for filing in the office of
  the register, it must be indorsed on the outside thereof with the  names
  of  the  parties thereto, the amount of indebtedness and the location of
  the property affected by such instrument.  Every  renewal  of  any  such
  instrument  must,  in addition to the aforesaid indorsements, be stamped
  or marked "renewal," and contain in the body thereof a reference to  the
  serial  number  and  the date of filing of the chattel mortgage or other
  instrument which it is desired to be continued for a further period, and
  the serial number and the date of filing of the latest previous  renewal
  thereof, if any.