On Gymnastic Exercises. 339 



ness, when a very important change may have taken place in 

 the condition of the bones, which a superficial observer may 

 not discover. Some of the vertebrae may have become anchy- 

 losed or firmly united by bone. In such a case (which is not 

 an uncommon one), violent exertions would be of no avail in 

 restoring the figure, and would be actually dangerous. Exer- 

 cises have been prescribed in cases even where the surgeon 

 was aware that anchylosis had taken place, and they have been 

 prescribed under the idea that where the spine is consolidated 

 by bone it is stronger than in any other part, and is therefore 

 in no danger of being broken even by the most violent exertion. 

 But the opinion, that the spine is strongest where it is anchy- 

 losed, is founded in ignorance of its structure; for it has been 

 proved, by various experiments, that the strength of the spine 

 mainly depends on the elasticity of the peculiar matter by 

 which the vertebrae are united. 



To demonstrate that the spinal column is not strengthened 

 but weakened by anchylosis, we have only to try the compara- 

 tive degree of strength in the several parts of a spine where 

 some of the vertebrae are united together by bone. In such 

 an experiment we shall find that the anchylosed part is so 

 weak and brittle, as to be fractured by the slightest jerk, while 

 it is very difficult to break the column at any part where the 

 intervertebral cartilages are entire. In further proof of this 

 fact, there are several fatal instances of fracture recorded, 

 where the spine was broken at an anchylosed part, by a com- 

 paratively slight degree of force. 



In cases of lateral curvature where the patient has a bad 

 constitution, it is not unusual for the bones to unite by 

 anchylosis ; but it is in another set of affections of the spine 

 that we have chiefly to dread the misapplication of exercises. 

 When the spine is attacked by scrophulous inflammation, 

 which often destroys the bodies of two or more of the vertebrae, 

 the condition of the patient at the commencement of the 

 disease is such, that the slightest exertion produces great pain 

 and an attack of fever; of course there can be no exercise 

 used at this period. But if the patient should recover so far 

 ajs to be able to walk, there is danger of particular exercises 

 being recommended to cure the deformity consequent upon 



