Model 1867 Hessen Mannschaften Pickelhaube
 
Model 1867 Hessen Mannschaften (Other Ranks) Pickelhaube.

This helmet was issued to at least three, or possibly four, different Hessen units in its lifetime; originally it was worn by Hessisches Garde Dragoner Regt in the Franco-Preußen war of 1870-71, then worn by the same regiment when they became Dragoner Regt Nr. 23, then issued to Infanterie-Leib Regt. Großherzogin (3. Großherzoglich Hessisches) Nr.117, and then possibly issued for a final time to a Hessen line Infantry regiment.

The body on this helmet is exceptionally thick and heavy, with all brass fittings.
A view of the issued Model 1867 Hessen lion Wappen (front plate).
A view of the rear of the helmet, showing the two external brass studs that secure the rear spine to the helmet shell.

Unlike other Pickelhaubes with cruciform spike bases where the front arm on the cruciform, is typically 1/2 the length of the other arms, on Hessen helmets the "arms" on the cruciform spike base appear to be equal in length. However, the front arm is actually a tiny bit shorter and always orientated to the front.
A side view of the Model 1867 Hessen Pickelhaube which illustrates the exceptionally high profile of a Franco-Preußen war helmet.

Note the small white spots of splashed white paint above the massive brass chinscales. Many old Pickelhauben have a few dots of paint on them somewhere from having been stored in a garage, cellar, or attic when painting was occurring.
The liner is the standard Pickelhaube heavy leather pattern. Note the large blackened circular reinforcement plate in the top of the skull to help maintain the helmet's shape. The original leather draw-string remains intact, although this is possibly from the last issue of the helmet, possibly as late as the early 1900s.
Here is where it gets interesting; this example was originally issued during the Franco-Preußen war of 1870-71 to Hessen Großherzoglich Hessisches Garde Dragoner Regt who wore a Pickelhaube with gilt fittings. When this Regiment was incorporated in the German Empire order of battle in 1871 as Dragoner Regt Nr. 23 (DR23) the helmet fittings were to be changed to silver.
This stamp indicates that the helmet was then stamped as being property of the newly-designated Dragoner Regt Nr. 23 until the old helmets with gilt fittings could be replaced by new helmets with silver fittings.

Note also the stamp of 1885. The first two numbers 18 are a single stamp, the 8 and 5 are stamped on individually, (the 8 was stamped upside down!) This date is either a later date stamp when the helmet was re-issued to an infantry Regt and DR23 finally received silver fitted helmets, or an indicator that some Squadrons in DR23 were still wearing gilt fittings as late as 1885, a full 14 years after they were authorized to wear silver fittings.
When DR23 finally received their helmets with silver fittings, this helmet was rolled over into the inventory of Infanterie-Leib Regt. Großherzogin (3. Großherzoglich Hessisches) Nr.117 (Mainz) XVIII Armee Korps as shown by the impressed "117 on the right rear visor.
However, this was also only temporary, as in 1897 to commemorate the bicentennial of IR117, the Grand Duke of Hessen awarded the regiment the dates "1697" and "1897" to be worn on either side of the lion Wappen. The new Wappens presumably took some time to arrive, but when they did, this old vet from the Franco-Preußen war was either retired from service, or issued once again, to a Hessen line Infantry Regiment.
Finally, a canteen-purchased label glued inside the skull showing the wearer to be a member of Infanterie-Leib Regt. Großherzogin (3. Großherzoglich Hessisches) Nr.117
The superb illustration to the left by Darko Pavlovic shows a mounted Reiter of the Hessisches Garde Dragoner Regt in the Franco-Preußen war of 1870-71 wearing this Pickelhaube.

From: Solka, M. (2005) German Armies 1870-71 (2) Prussia's Allies (Men at Arms 422).Osprey Publishing, Midland House Oxford.