Today, there is an enormous understanding of the anatomy of bone formation compared to that available to Duhamel du Monceau and John Hunter when they developed the then prolific theories. of the anatomy of bone growth. Duhamel proved, in 1742, that bone is first formed in the periosteum and grows in superimposed layers. Hunter, through his experiments, showed that the bone lengthens by juxtaposing layers and that the medullary cavity (trabecular bone) develops by resorption of the internal layers of the bone. It also showed that bone ends exhibit remodeling via cycles of bone formation and resorption. Duhamel du Monceau used madder tincture, an extract from the root of the Rubia tincterium tree, in a staining technique that allowed him to show that bones increase in thickness. via interstitial growth. This technique was previously practiced by Belchier. Duhamel gave bran mixed with madder and gave it to a rooster. He then observed the red coloring of the bones caused by the dye. Duhamel mixed powdered madder with bran and fed it to pigeons, turkeys, and chickens to ensure that madder was causing the changes seen on the bones and not other ingredients. Sixteen days later, the animal was killed and all its bones had turned red again. By dissection, Duhamel observed that only the bones had turned red and that all other internal and external parts of the animal retained their natural color. Duhamel therefore established that the color of the bones was due solely to the dye, which affected only the bones and no other tissue. Thus, by alternating a madder-treated diet with a normal diet, he observed a series of alternating layers of red and white bones, each corresponding to a change in the animal's diet, thus proving that gr bone. ..... middle of paper... ...years later, after sawing the tree, he found that the hardened part of the branch had not increased in size. Duhamel was thus able to observe the periosteal growth of bones based on the analogy with the growth of trees. To study the longitudinal growth of a long bone, Duhamel inserted needles at equal intervals into the femur of a newly hatched chick. Dissection of the chick's femur a fortnight later revealed that the impressions made by the needles were separated by varied intervals, the smallest near the trabecular region and the largest near the cortical bone as hardening begins. in the trabecular bone and gradually continues towards the cortical bone. This proved that different parts of the bone do not all grow in the same way but that trabecular bone grows more than cortical bone. This phenomenon is now known as longitudinal bone growth..