The Big Crack and What’s Underneath It
In 1942, there was a war on, construction standards where not well developed, and concrete masonry systems were not nearly as prevalent as they are today. Which is a round about way of saying, that it looks like old construction that does not utilize contemporary practices.

To me, it looks like horizontal reinforcing. Today, it would probably be done with a prefabricated wire 'ladder' or similar module. In the old days, those weren't common so it is probably a small reinforcing bar (perhaps 1/4", but that's just a guess based on the time frame).

For peace of mind, it might make sense to hire a Professional Engineer to take a look; evaluate the situation and provide advice. Then there is will be more information for making an informed decision regarding what, if anything, needs doing; when it needs to be done; and how feasible it is to tackle on your own versus hiring construction staff.