I have found the following quote of Weston Walch on https://philosophy.lander.edu:
It cannot be proved that government ownership of railroads has succeeded in other countries. Therefore, government ownership of the railroads should not be adopted in this country.
The website itself gives a reference to his book "On Conception". I would like to use this quote, but don't know how to reference it, should I just reference the original work?
Another example that is even trickier is the following quote of William Harvey:
[W]hat I shall state I wish not to be taken as if I thought it a voice from an oracle … I claim, however, that liberty … to put forward as true such things as appear to be probable, until proved to be manifestly false.
It is not a full quote, but a modified version of the original made by the author of the article on the https://philosophy.lander.edu. If I were to use the quote in this form should I also only reference the source which the author used without mentioning the website from which I took it?