Yes, you are correct. Carol Serr, who originally posted the message, pointed
this out as well. She forwarded the following web site that confirms this:

http://www.lib.umich.edu/eebo/docs/dox/medical.html

Ben Pykles

Quoting Juston Fareillo <[log in to unmask]>:

> Juston Fariello
> Archaeologist
> URS Corporation
> 8181 E. Tufts Ave.
> Denver, Co. 80237
> 303-796-4623
> [log in to unmask]
>
>
> I am unfamiliar with the W. B. M. Co., but believe that the Z symbol
> represents ounces. If you look close, the hook at the top is of the Z is a
> O. So the symbol is OZ or ounces. I've only seen this symbol on bottles
> with CC measurments on one side and the OZ symbol on the other with lines
> to deliniate measurments. Take an ounce of water and see if it fills to the
> line.
>