12 TEANSACTIONS LIVEBPOOL BIOLOGICAL SOCIETY. 



These writers attach, therefore, a clear and simple func- 

 tional meaning to this collection which composes the 

 spinal root. They point to the fact that stimulation of 

 this root or that root produces a movement of the limb 

 which is of some definite kind, such as a flexion of the 

 elbow, flexion of the fingers, &c. The movement evoked 

 they consider one which indicates that the nerve-fibres 

 associated together in the motor root are associated there 

 in order to, by acting contemporaneously, execute a highly 

 co-ordinate functional synergy of muscles. By synergetic 

 muscles are understood those muscles which, in natural 

 movements, contract harmoniously together to execute 

 a movement. I find nothing which is really valid evi- 

 dence for this view and much to the contrary. The 

 mere inspection of a movement of the limb without 

 further analysis of it is very insecure a guide by which to 

 judge of its natural character. The joints and muscles of 

 the limb have been evolved contemporaneously and 

 together in the course of the history of the individual and 

 of the species. No muscle can, therefore, be thrown into 

 action which will move the limb in any which is an 

 unnatural direction. Our knowledge of the synthesis of 

 the natural movements of the body out of the contractions 

 of the individual muscles is extremely meagre. The 

 names given, for instance, to many of the muscles of the 

 human arm are misleading rather than helpful as regards 

 the movements they produce. The resolution of the com- 

 bined movements into their components require data 

 hardly obtainable, because requiring isolated contraction 

 of individual muscles in life, and the alteration of the 

 lengths and tensions and elasticities of the muscles after 

 death, precludes the possibility of dealing with them even 

 approximately accurately by examination in the dissecting- 

 room. Thus few realise that the gastrocnemius muscle 



