13. V. 08 (13th May 1908)

The following text is a bit difficult to read but some words can be made out:

"L. M.!"   (speak to)
"Herzl. Gruesse, auf Deinem ltz. ..., Dein ...  (name?).  Brief folgt."

(including abbreviations:  Herzliche Gruesse, auf Deinem letzten ...: 
"Kind regards, to your last ..., Your ... Letter follows.")