As far as i can tell it is only the 1851 Census that is missing for Henryville .... all other records are in tact ..
there is a n 1861 1871 and 1891 census recording that are located in Archives in Ottawa. i do not know if they have any intention of putting them out on the inter net , but it cetain would help us all.
In any case we all have acces to the mirco film records.. it is only a matter of finding out how we can get to look at them the only expericen I have had is with the 1851 records and those were at my local Genealogy Society. I have two phot copy pages of the 1891 that one of my relatives made for Clarenceville but it only shows our Macfie families....
for certain the records exist at least......
On my Henryville web page
http://freepages.genealogy.rootsweb.com/~macfie/henryville.h... you will find the address of the city hall. I have suggested so fat to any one tracing there since it most French Roman Catholic records that they wrtie a letter to the local Priest asking him to check out the records , then to mail that letter to the City Hall with another letter asking them to give the the first letter to the local Priest ......
i do not know if any one has tried this or if it works, but as i have done no tracing in this area i do not know of a better way
Douglas