Looks like a Disston. However, it's not a medical bone saw knife. It's for general kitchen use. Disston just lists it as a saw knife, but it is in the meat saw section in their 1918 catalog. This type of Saw Knife was first made and patented by W. Stillman who according to the Book "Handsaw makers of North America" was around in the late 1830's. In volume IV of the Civil war Collectors Encyclopedia page 122 they show one similar made by E.M Boynton and stamped US and which they identify as a US medical dept. bone saw. Boynton according to the above book, made saws from 1869-87 so that negates the mention in the book of being used in the Civil war.