of the Vegeto- Alkaline Salts. 253 



The appearances afforded by the electro-chemical decom- 

 position of these salts led to the question, how far the bases 

 might be discovered by the voltaic test in the infusions of 

 opium and bark ; but. when these are treated in the usual way, 

 there is no distinct separation of difficulty soluble alkaline 

 matter, as might have been expected, in consequence, probably, 

 of the multiplicity of substances that are present : nor is strich- 

 nine separable in this way from the infusion of nux vomica. 



SOME OBSERVATIONS ON DR. ARNOTTS EXPLANATION 

 OF THE NATURE OF STAMMERING. 



BY MARSHALL HALL, M.D., F.R.S.E., &c., &c. 



T WAS much struck, in the first instance, with the simplicity 

 of Dr. Arnott's explanation of the defect in speech termed 

 stammering, in his interesting and popular work, entitled 

 * Elements of Physics.' I, however, soon perceived its fallacy; 

 and as this has not hitherto, I believe, been pointed out, it 

 may not be amiss for me to do so briefly in this place. 



I will first copy Dr. Arnotfs view in his own words. That 

 gentleman states, that * * The most common case of stuttering 

 is not (as has been almost universally believed), where the 

 individual has a difficulty in respect to some particular letter 

 or articulation, by the disobedience, to the will or power of 

 association, of the parts of the mouth which should form it, 

 but where the spasmodic interruption occurs altogether behind 

 or beyond the mouth, viz., in the glottis, so as to affect all the 

 articulations equally. To a person ignorant of anatomy, and 

 therefore knowing not what or where the glottis is, it may be 

 sufficient explanation to say, that it is the slit or narrow open- 

 ing at the top of the windpipe, by which the air passes to and 

 from the lungs being situated just behind the root of the 

 tongue. It is that which is felt to close suddenly in hiccup, 

 arresting the ingress of air, and that which closes, to prevent 

 the egress of air from the chest of a person lifting a heavy 



* Elements of Physics ; vol. ii. Part I. Appendix pp. v viii. 

 VOL. I. FEB. 1831. S 



