Rubuta ci gaba ga wannan sakin layi - Dr. McHenry ya shiga United States Volunteers a 1898, a matsayin likitan kwangila tare da mukamin kyaftin. Ya yi aiki a cikin Yakin Spain-Amurka a Cuba, da tawayen Philippines
, kuma a kasar Sin. A shekara ta 1903, an sallami Dr. McHenry daga rundunar likitocin Amurka da mukamin Manjo.