An excerpt from the wonderful History archive that Dr. Joseph Keating entrusted to chiro.org. These pdf’s form the data source that Dr. Keating used for his many published articles on chiropractic history and are available for browsing.

Excerpted from the pdf on Clarence W. Weiant, DC.

“Chiropractic arrived so recently in Mexico, that the history of its
invasion into this new territory would hardly be worth relating, were
it not for the fact that in so doing I might convey to those who regard
Mexico as a prospective field of practice some idea of the conditions
they may expect to encounter.
When I left Davenport and THE PSC, it was with the exalted
notion that I was to be the pioneer Chiropractor of the whole
Mexican republic, but it was not necessary to go any farther than San
Antonio to have that notion dispelled, for there I learned through Dr.
Gurden , president of the Texas Chiropractic College, that three of his
graduates had already located in Mexican towns. The first, if I am
not mistaken, was Dr. S. Voquero, a native of South America, who, a
few months previous had opened an office in Monterey, in the state
of Nuevo Leon, northern Mexico, and the report was that he was
having noteworthy success.”