Use of complementary methods for experimental animal studies of digestion in the 18th and 19th centuries

The use of complementary methods to animal experiments is very old. Spallanzani (1785) apparently was the first who used such methods in his studies on digestion. In the 19th century Eberle, Pappenheim, Purkyné and others used on their studies on the process of digestion artificial chyme. On this view, Beaumont published in 1834 an interesting paper on the digestion of men after observations in vivo and parallel in vitro. All papers show, that the using of complementary methods to animal experiments was not unusual in the 19th century.