316 INNEHVATION. [CHAP.XI. 



effectually calms this excited state. Conium and belladonna have 

 been, in our hands, very useful in relieving the cramps and start- 

 ings in paraplegic cases. We have seen no marked benefit from 

 hydrocyanic acid, although we have administered it freely : on the 

 contrary, we fear that both it and the two former substances might, 

 if given in large doses, have the contrary effect, and increase the 

 polarity of the cord. Certain it is, that animals poisoned by large 

 doses of these drugs always die in a state of general convulsion, 

 and that in the instances where they have acted as poisons on the 

 human subject, general convulsions have come on a longer or 

 shorter time before death. 



Functions of the Columns of the Cord. Having so far determined 

 the functions of the entire cord, the next question which demands 

 our attention is, whether its columns have special functions, in 

 accordance with those of the separate roots of the nerves. Could 

 it be proved that the anterior or motor roots were exclusively 

 connected with the antero-lateral columns, and that the posterior 

 or sensitive ones arose exclusively from the posterior columns, 

 then there would be good anatomical grounds for the doctrine 

 so long erroneously prevalent, that the functions of these columns 

 coincided with those of the roots, that the posterior columns were 

 sensitive, and the anterior motor: but nothing is more certain, 

 than that both roots are connected with the antero-lateral columns; 

 and it is a matter of some doubt, whether the posterior roots have 

 any connexion at all with the posterior columns. Hence, all that 

 anatomy warrants us in stating is, that the antero-lateral columns 

 are probably compound in function, both motor and sensitive. 

 Respecting the office of the posterior columns, little can be said. 

 Are they sensitive ? Were they so, it might be expected that they 

 would exhibit an obvious enlargement at the situations which cor- 

 respond to the origins of the largest sensitive nerves; but it is 

 remarkable that the posterior columns exhibit little variation of 

 size throughout the entire length of the cord. And it is not likely 

 they can be motor, inasmuch as the apparent origin of the motor 

 roots is so distinctly remote from them. 



Comparative anatomy throws no light on this question. New 

 and careful researches are much needed to determine the develop- 

 ment of the posterior columns, and the exact relation which the 

 posterior roots bear to them in different classes of animals. 



Nor do we derive much positive knowledge from the researches 

 of the morbid anatomist. Cases, indeed, are on record, which shew 

 that disease of the posterior columns does not necessarily destroy 



