2 Twitch or castration clamp?
Our main sources for ancient methods of castration are Columella’s De re rustica and an anonymous work on care for equines, referred to as the Mulomedicina Chironis. Columella described the castration of calves by destroying the testicles gradually with a piece of cleft fennel. This has been taken as clamping the scrotum and spermatic cords between pieces of wood, thereby cutting of the blood supply, resulting in the slow atrophy of the testicles. Older bulls received the same treatment, followed by an operative procedure: the scrotum was incised and the testicles exposed. The epididymal tissues were removed from the testicles, but left attached to the spermatic cords and cremaster muscles. It was believed that haemorrhage was less likely to occur after this procedure (Adams 1990, 268, 270).
The Mulomedicina has several passages that describe the castration of equines. The cases show some variety, but all require an operative procedure. Mulomedicina 726 instructs that to start with, a ligature should be tied, apparently around the neck of the scrotum, to prevent the testicles to ‘flee back’, that is, move up into the inguinal canal. Then an incision is made by a sharp knife (ferrum acutum). After that, the testicles are exposed and removed with the knife. Mulomedicina 683 starts differently by exposing the spermatic cord and breaking it, or cutting it where it is thinnest. However, the testicles are eventually cut out as well, so it is not very clear why the initial procedure differs. Mulomedicina 317 concerns castrating ‘by fire’. This also starts with an incision in the scrotum and exposing the testicles. Then the testicles are cut with white hot irons. This procedure was followed to avoid bleeding, which was assumed to increase the risk of infection of the wounds (Adams 1990, 268-270). Now that we have knowledge of some procedures for the castration of cattle and equines as described in ancient texts, we have enough information to argue the function of the large pincers.
2.1 The Aix-en-Provence altarnext section
The scene to the right of the altar (Fig. 2) shows a man holding the bent leg of a horse, possibly a farrier trimming the hoof.The scene to the left shows the clipping of the mane. There is no reference to castration found in the picture at all. If the object shown was used for castration, the person handling the horse would be depicted to the rear or beside the horses. If one accepts that the object at the centre of the altar is in any way connected to the two scenes, an interpretation of the object as a twitch is the only realistic option. One could argue that the twitching of the horse is not recognisable exactly, but at least twitching could be applied to the horses during both actions.
2.2 The physiology of a horse in relation to castration
In the ancient sources concerning castration mentioned above, clamping the scrotum only refers to cattle, sometimes combined with an operative procedure. In the case of equines, the scrotum is tied with a cord and castration always involves an operation. There is a good physiological reason for this. Bulls have a low hanging scrotum, which leaves ample room to place clamps. The scrotum of a stallion on the other hand is situated higher up, almost in the abdomen. There is no room to place a clamp, only to tie it with a cord to prevent the testicles moving back up into the abdomen. Since the objects under discussion were definitely used on equines (see the Aix-en-Provence altar above), the physiology of horses indicates that these objects could not have been used as castration clamps.
2.3 The decorated pincers from London
Fig. 4 shows a pair of dented pincers in bronze, decorated with large horse heads at the top, close to the hinge, and slightly smaller heads of several divinities and bulls along the arms of the object, and finally lion heads forming the knob of the handles. An argument against an interpretation as a twitch could be that the heads on the London pincers depict both horse and cattle, and that a twitch is not used on cattle (or at least not in the same form). However, the presence of divinities and lions make clear that the heads are not necessarily connected to the function of the object. Most likely the heads are symbolic in nature, referring to a ritual use of the object, not to the specific function.
Fig. 4 The decorated pincers from London (after Kolling 1973, Tafel 70).
2.4 Functionality and appearance of the pincers
If we take a closer look at the pincers that were published by Kolling, it appears that most of the pincers do not close completely. The decorated pincers from Augst are the best example (Fig. 5 left): in a closed situation, the serrated edges of the pincers are about 1 cm. apart. This is also true of other examples (Fig. 5 right). This is consistent with a twitch, since the upper lip of a horse must be pushed but not squashed completely. This is however in conflict with castration clamps, since the clamping of a bull's scrotum would need the total closure of the clamp.
Fig. 5 Left: the decorated bronze pincers from Augst. Right: iron pincers from the Saarland (after Kolling 1973, Tafel 70 and Abb. 1).
In figure 6, several 19th-century castration clamps are shown to the left and in the middle, and a 19th-century twitch on the right. The first observation is that the twitch is made from iron and shows resemblance both to the Roman period pincers as well as to the 21st-century twitch in figure 3. The second observation is that the castration clamps do not resemble the Roman period pincers at all, and are made from wood. This is consistent with the ancient sources concerning castration, which mention wooden clamps.
Fig. 6 Left and middle: 19th-century castration clamps. Right: 19th century twitch (photographs kindly provided by the Museum for Veterinary Medicine, Utrecht University).
2.5 Weight of the iron pincers
An argument against an interpretation as a twitch is that the iron objects are too large and heavy. However, the twitch could have been held by the owner of the horse (as is custom today), so not all the weight of the object is on the horse’s head. Furthermore, the object in figure 5 (right) shows a slit, which could be used to attach the object to the horse's bridle, so the weight is not dragging on the lip. The same argument can also be brought forward against the use as castration clamps. The clamping of the scrotum of cattle should be maintained for several hours. Given the weight of the iron objects, that would be really painful. No doubt this is one of the reasons that the ancient texts mention wooden clamps only, and that the surviving clamps are also from wood (Fig. 6).
In my opinion, there is no good reason to assume that the objects under discussion have ever been used as castration clamps. All available evidence points to the interpretation as twitches, used to sedate horses.