938 NATURE AND LIFE. 
Wurzburg, Bernhard Heine. He removed more or less 
extensive portions of bone from living animals. In some — 
cases he effected the removal of half of the bones he oper- 
ated on. The parts destroyed were reproduced after a few 
months, and the limbs were restored to their original con- 
dition. 
Still more famous than Heine’s are the patient and 
skillful labors of Flourens. The varied experiments of 
this learned physiologist clearly established the truth of - 
the first observation of Duhamel. In the words of Flourens, 
‘Since it is the periosteum which produces the bone, I 
must of course be able to get bone wherever I can have 
periosteum, that is to say, wherever I can succeed in car- 
rying or introducing periosteum, I shall be able to increase 
the number of an animal’s bones; if I choose, I shall suc- 
ceed in giving it bones which naturally it did not have.” 
Among other experiments made to prove the truth of this 
proposition, Flourens conceived the idea of piercing a bone 
and inserting in it a little silver tube. The periosteum 
engaged in this tube became thicker there, swelled, and 
produced a cartilage which soon became bone. A skillful 
surgeon of Lyons, Ollier, cut out long ribbons of periosteum 
in an animal, leaving them still adhering to the bone by a 
little strip, and then twisted them round the neighboring 
muscles. After a certain time, this ossified periosteum 
had produced bones of circular shape, in spirals, in figures 
of eight, etc., according to the manner of twisting the peri- 
osteal strips about the parts near them. 
In all these experiments, periosteum was used provided 
with the very delicate layer which adheres to it, and sepa- 
rates it from the bone. Now, Robin has proved that in the 
adult this layer is formed of bony cells, and of cartilagi- 
nous substance when a bone in course of development is 
operated on. It is in this that the bone-making power 
dwells, and, when the periosteum is stripped of this, it be- 
