Bitting rig rig." It is the use of additional reins such as the overcheck, or the use of leverage to place the horse's head in a set position that turns a classic surcingle into a bitting rig. Both a bitting rig and a classic surcingle with side reins are intended only to be used while longeing a horse. They are not to be used on a horse that is standing in a stall (though this is a very common type of misuse), nor are they used while riding. However, the surcingle and side reins are used as safety tools in the sport
Animal testing on frogs which reaches its reproductive age in five months rather than one to two years (as in "X. laevis"), facilitating faster studies across generations. The genome sequence of "X. tropicalis" was scheduled to be completed by 2015 at the latest. Frogs are widely used in classroom dissections and teaching exercises. Animal testing on frogs Frogs have been used in animal tests throughout the history of biomedical science. Eighteenth-century biologist Luigi Galvani discovered the link between electricity and the nervous system through studying frogs. The African clawed frog or platanna, "Xenopus laevis", was first widely used in laboratories in pregnancy assays in