While Calculus may nominally have been invented a couple of centuries earlier, even by 1869 it still had a lot of development to go through before it would approach the relative ease of modern calculus. Limits were still only a few decades old, with the modern notation for it not developed until 1908[1]. It takes a long time for things to go from the cutting edge of math down to pre-college curricula. Perhaps some students had been exposed to it, but testing for it on the entrance exam may not have provided much information for the examiners.

In fact, reading that sort of makes me curious about what pedagogical approach was taken to teach pre-limit calculus.

[1]: http://en.wikipedia.org/wiki/Limit_of_a_function