My education is sorely lacking. I never heard the Panama Canal referred to as the Isthmian Canal, but saw a reference to it today when I went through a truly fascinating set of lantern slides from the William Gorgas era of the Canal. Here are two of several dozen that date from about 1902 to 1914. I wish I could scan them all.
This first one is a lovely hand-tinted lantern slide of Spanish laborers.
This second one is a chart (table?) showing a marked decrease in fatalities from various diseases, supposedly when sanitary measures were put in place- such as covering food, digging drainage ditches, oiling still bodies of water, etc. Note the Americans giving themselves a big old pat on the back.