Since that time documents have come to light that suggest 1849 is NOT the correct birth year for James. The 1871 Canadian Census appears to show his age as "27" making his birth year "about 1844" as it appears in an Ancestry.com transcription.
We also know from his mother's gravestone that she died in 1847 making an 1849 DOB for James impossible.
James father Samuel Langin did not remarry until 1850 when he married Margret Ferguson. Making an 1849 birth by the "new" step mother unlikely.
The 1861 Canadian Census and 1880 U.S. Census records also appear to show that the 1849 DOB is probably incorrect and 1844 is much more likely.