Is anyone familiar with how to locate records of German soldiers from the Franco-Prussian War (aka. Franco-German War, War of 1870) or any records whatsoever about particular regiments within the German army? 
I have a family birth record from 1871 from a village in the Nassau area of Hessen which indicates the following:
 
"Der Vater des Kindes ist zur Zeit in Frankreich als Fusilier des XI. Armeecorps 21. Division 42 Brigade 2 nassauisches Infanterie-Regiment Numero 88, 10 Compagnie"

"The child's father is currently in France as a Fusilier of the XI. Army Corps 21st Division 42 Brigade 2 Nassau Infantry Regiment Number 88, 10 Company

Thanks for your ideas and input.
Michael Rubin
Boston, MA  USA