What Is The Concept Behind Gizzard Of The Hawk?

Reaumur carried out the experiments which showed that the meat actually disappears from the regurtated capsule, indicating the gizzard did not break up the food mechanically as had long been supposed.

The Jesuit and biologist was particularly fond of unusual experiments, especially when they contradicted the biblical point of view. He had demonstrated the power of regeneration in brilliant experiment on the ability of lizards to regrow lost tails. According to published lost tails. According to published reports, he was the first person to carry out experiment of artificial insemination (with dogs) whish, in itself, was somewhat outside the normal activities of a priest, even for a Jesuit.

However, it took about 30 years before Spallanzani paid closer attention to Reaumur's experiments. In 1783, he went to falconry and arranged for meat-filled, perforated metal capsule to be fed to falcons and buzzards. As Reaumur had previously observed, the capsule were again empty after regurgitation.

This did not satisfied Spallanzani. He went further. He concluded that the force altering the food must be contained in the gastric juice. This time, he filled the same metal capsule with a small sponge which soaked up gastric juice while inside the bird of prey. He then placed the gastric juice in the vessel with pieces of meat which, to Spallanzani's delight, were subsequently dissolved. For the first time it was thereby clear that gastric juice contains a substance which dissolve proteins. These results became well known in an astonishingly short period of time.