REGENERATION AFTER EXARTICULATION 113 
This substantiates Wendelstadt’s conclusion that ‘osteoblasts’ 
(in reality chondroblasts) arising from the lining of the marrow 
cavity contribute to the new formation (of cartilage). Glaeser, 
however, derives the axial cartilage from periosteal and connec- 
tive tissue fibrillae exclusively. He thinks that cartilage may oc- 
easionally arise from bone-marrow though this is doubtful. The 
origin of a part of this cartilage from cells of the old (distal 
epiphyseal) cartilage naturally could not occur in the experiments 
of Wendelstadt and Glaeser since the distal epiphysis was always 
removed in their operations. Glaeser nevertheless states that 
regeneration from old cartilage, either from the cells or the matrix 
does not occur. The writer is unable to determine from Glaeser’s 
account upon what experiment this conclusion is based. That 
giant-cells in certain regions. break down the matrix and open up 
the capsules is true but in Diemyctylus, at least, the cartilage 
cells certainly do not degenerate. Evidences of further activity 
are abundant in this material including the frequent presence 
of mitosis. 
During the early stages in the formation of axial cartilage, 
the cells of the periosteum also begin to form cartilage. The 
site of this new formation is at first some distance from the distal 
end of the femur and entirely distinct from that of the axial 
cartilage. It may be called periosteal cartilage, or using Glaeser’s 
term, peripheral cartilage. An early stage of its growth is 
shown in figure 1, Per.C; a later one in figure 2, Per.C. The 
formation of peripheral (periosteal) cartilage is mentioned by 
most workers on regeneration and there is no need to discuss 
it at length. In all cases it first appears at some distance proxi- 
mal to the wound and gradually spreads distalward until it 
forms a continuous collar around the shaft reaching to the distal 
end (fig. 3, Per.C.). Cornil and Coudray (703) described a 
similar formation in the healing of experimentally produced 
fractures in a mammal (rabbit). The first phenomena of repair, 
they state, are to be found at some distance from the fracture, 
that is the formation of peripheral (periosteal) cartilage. 
Whether or not the axial] cartilage always appears first could 
not be determined. In some cases the peripheral cartilage was 
THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 25, NO. 1 
