As a boy, he, like his older brother Robert, collected insects in the country around Duns, and rocks such as copper ore from old mine workings.

[3] He volunteered the next year to the Foreign Missions Committee and married Erasma daughter of William Hull of Olney.

Hislop was returning from a visit to some ruins at Taklghat during the night of 4/5 September 1863, when his horse fell into the water in darkness in the Bori river and he was drowned.

[6] Sir Richard Temple, who became chief commissioner of the central provinces in 1862, praised Hislop as "among the most gifted and accomplished missionaries whom this generation has seen in India"; as being notable "for philology and antiquarian research"; and "for physical science, especially botany and geology".

[7] Hislop was assisted by another Free Church of Scotland missionary, Robert Hunter (1823-1897), who later edited the Encyclopædic Dictionary.

Papers by Hislop (after Hunter became ill and returned to Britain) for the Geological Society included "Tertiary Deposits associated with Trap-Rock in the East Indies, and Fossil-shells from those deposits"; "On the Age of the fossiliferous thin-bedded Sandstone and Coal of Nagpur";[8] "Supplementary Note on the Plant-bearing Sandstone of Central India";[9] and "Fossil Teeth and Bones of Reptiles from Central India".

[8] The finds by Hislop and Hunter included a new species of Labyrinthodont reptile, Brachyops laticeps that was described by Richard Owen in 1854.

[3] According to the entry on Hislop in the Dictionary of National Biography, he also worked on the geology of the Nagpur region and published his findings in three papers for the British Association in 1859.