The Collaborative International Dictionary of English v.0.48:

Systematic \Sys`tem*at"ic\, Systematical \Sys`tem*at"ic*al\, a.
   [Gr. ?: cf. F. syst['e]matique.]
   1. Of or pertaining to system; consisting in system;
      methodical; formed with regular connection and adaptation
      or subordination of parts to each other, and to the design
      of the whole; as, a systematic arrangement of plants or
      animals; a systematic course of study.
      [1913 Webster]

            Now we deal much in essays, and unreasonably despise
            systematical learning; whereas our fathers had a
            just value for regularity and systems. --I. Watts.
      [1913 Webster]

            A representation of phenomena, in order to answer
            the purposes of science, must be systematic.
                                                  --Whewell.
      [1913 Webster]

   2. Proceeding according to system, or regular method; as, a
      systematic writer; systematic benevolence.
      [1913 Webster]

   3. Pertaining to the system of the world; cosmical.
      [1913 Webster]

            These ends may be called cosmical, or systematical.
                                                  --Boyle.
      [1913 Webster]

   4. (Med.) Affecting successively the different parts of the
      system or set of nervous fibres; as, systematic
      degeneration.
      [1913 Webster]

   Systematic theology. See under Theology.
      [1913 Webster]