Staff Woes

I came across a picture recently of General Alfred Pleasonton and his staff taken in Warrenton, Virginia in October of 1863 (the picture itself can be found at CivilWarPhotos.net and the Library of Congress). I'm not personally a fan of Pleasonton, but as I read the caption something jumped out at me.

Of the 21 officers listed on his staff, 7 were Regulars. They included the Colonel of the 1st Cavalry (who surely had something better to do, like leading his regiment), 2 lieutenants of the 5th Cavalry, and a captain and 3 lieutenants of the 6th Cavalry. Additionally, there was a lieutenant colonel, a captain and a lieutenant from the 6th Pennsylvania Cavalry. To say the least, the Reserve Brigade was well-represented, composing half of his staff. No wonder the regular regiments were constantly short officers, as Pleasonton was hardly the only officer doing this.

Interestingly enough, he didn't have any officers from his own regiment (as much as it pains me to admit it, he was an officer in the 2nd Cavalry throughout the war) on his staff at this time. I wonder why....