We propose observations of IR fine-structure emission lines in the
 lowest-luminosity known Seyfert 1 nucleus in NGC4395.  This object is
 of unique value for probing the characteristics of active galactic
 nuclei (AGNs) at low luminosity.  Data from this proposal combined
 with observations scheduled in Guaranteed Time Programmes will provide
 insights into luminosity-dependent behavior indicative of the
 structure and energetics of AGNs and quasars.  The nucleus of NGC4395
 is also of great interest as an unambiguous AGN with luminosity
 matching that of the Galactic center.  Comparison of observations of
 NGC4395 with those of Sgr A West thus may provide new insight into the
 degree to which the Milky Way hosts an active nucleus.  Observations
 will be obtained under the current proposal with the SWS.  The
 measured lines will be used to quantify abundances, densities, and
 ionization conditions in the narrow-line region of this AGN.
 The present study will help complete a multiwavelength picture of
 NGC4395's nucleus, when combined with recent and ongoing observations
 in the radio, optical, UV, and X-ray spectral regions.  The IR
 transitions add information beyond what is available at optical or UV
 wavelengths, since these lines are generally insensitive to electron
 temperature, which aids in abundance determinations, and probe regions
 that may suffer severe extinction at shorter wavelengths.
 Measurements of the local continuum accompanying observations of the
 lines can also be used to quantify the amount of dust reprocessing of
 radiation in this AGN.  Wavelength regions appropriate for detection
 of coronal features will also be observed with the SWS in parallel
 when strong lines tracing the narrow-line region are unavailable in
 merged mode.  The lines to be studied under this program are
 difficult or impossible to measure in suborbital observations.