Gap between bricks in old house.... why?

My house was built in the early 50s as far as we can figure. It’s a raised bungalow. The cinderblocks that make up the foundation come above the ground level maybe a foot and a half, then the red brick takes over.

On the very first row of bricks (first on top of the cinderblock) there is no mortar between every second brick. It’s just a gap. As far as I can see it goes all the way through to the other side.

At first I thought “oh, the mortar over there is gone, I’ll have to replace that”. Then I noticed the pattern. Every second brick, all the way around the house, on the first row of brick only.

Why is this here? Is it an old method of ventilaing the basement? Is it a mistake? Can I fill these gaps without causing a problem? I find a lot of lawn ants are finding their way in the house, and I’m sure these gaps aren’t helping me combat that problem.


Weep Holes

Google “Weep Holes” and you should find plenty of info.