I beg to differ on Arthur's statement that the only colored personnel one would have seen in a white unit were occupied in the menial tasks of cooking, etc., as there were also Chinese, Filipinos, and others who were in the combat occupations. We all know about Joseph Pierce of the 14th Connecticut and John Tomney of the 70th New York, but there were quite a number of others who are listed at my site ASIANS IN THE CIVIL WAR, accessible via:
http://hub.dataline.net.au/~tfoen/
There were also Asians who served in some of the colored units.