Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
A three year old riding horse was entered into the Stange Memorial Clinic an March 28, 1957. The owner had purchased the horse as a gelding, but found him to be rather high spirited and difficult to handle at times. Upon examination, no distinguishable structures were palpable in the scrotum. All feed was withheld and exploratory surgery for a cryptorchid testicle was planned far the following day.
"Castration of a (Gelding?),"
Iowa State University Veterinarian: Vol. 19
, Article 9.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol19/iss3/9