238 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, Oilier, 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- 



