Carl Linnaeus, The Lapland Journey, translated by Peter Graves (Edinburgh: Lockharton Press, 1995), p. 137.
The Mountains [2], 15/07/1732, ¶711:
A fortnight before Michaelmas and when the animal is 2 1/2 years old, the farmer gets someone to hold it by the horns while he goes to the rear and bites into the scrotum with his teeth in such a way that it does not make a hole in the skin for, if that were to happen, the reindeer would die. Then he squeezes it with his fingers a little and does the same thing on the other side, as long as the reindeer has not started kicking. The animal is healthy again within a week, though it is slightly indisposed at first and only able to follow the rest of the herd with difficulty. This is a technique which is both interesting and noteworthy; it deserves to be passed on.