Joint Counties Lunatic Asylum

[Kiki1958]

Does anybody know what legal procedures were required, between 1881-1891, to commit a person to the Asylum?  The records for this Asylum are at the National Library of Wales, but do not seem to be digitised. 

Would there be any newspaper reports, or legal journals covering the dates of 1881-1892 which would mention the individuals committed?

My Great great great Grandfather, Henry Hignell ( sometimes spelled "Hignett" by census takers) was a patient in the Asylum by the 1891 Census, and died in June 1892. 

I'd prefer any digital databases/archives, so I wouldn't have to put anybody to the trouble of doing research.