on the Rejlejc Function of the Spinal Marrow, 189 



sciousness, but still may excite violent impressions on the 

 spinal marrow ; as, for instance, the permanent contraction of 

 the sphincters from the stimulus of the excrement and of the 

 urine. But Dr. Marshall Hall goes too far, when he sup- 

 poses that in health every motion on true sensation is induced 

 by the will, and that all excitations of sensitive parts in the 

 reflected motions are without sensation. For the reflected 

 motions of sneezing, coughing, and many others follow actual 

 sensations*. 



" The reflected motions, and the involuntary not reflected 

 motions are not to be confounded with one another. If the 

 rima glottidis of an animal be touched, says \^i\ Marshall 

 Hall, a contraction takes place ; the same, when the heart is 

 touched. By removal of the brain no alteration ensues ; but 

 if the medulla oblongata be removed, the contractions of the 

 larynx on stimuli cease, while those of the heart continue. The 

 action of stimuli on the heart is an immediate one dependent on 

 its irritability; a stimulus applied to the larynx must, on the 

 contrary, be propagated to the medulla oblongata, and the con- 

 traction results indirectly from it. In a snake after the removal 

 of the head a motion of the larynx ensued ; it was drawn down- 

 wards and closed, as soon as Dr. Marshall Hall touched a spot 

 within the teeth of the lower jaw or the nasal apertures. After 

 removal of the medulla oblongata this ceased. Lastly, he men- 

 tions as belonging to the reflex function, the winking of 

 the eyelids when they are touched; the peculiar action on the 

 respiration by tickling, or when cold water is thrown into the 

 face; sneezing from stimuli of the nasal mucous membrane; 

 cough; vomiting from stimuli of the larynx or pharynx; te- 

 nesmus from stimulation of the rectum ; and strangury from 

 that of the bladder. We see that the spasms in diseases may 

 have very different sources. There are, for instance, spas- 

 modic affections which have their seat in the motor nerves 

 themselves, and others which have their cause in the brain 

 and spinal marrow ; but there are also reflected spasms, whose 

 cause lies in stimulation of sensitive nerves, as those which often 

 take place after intestinal stimulation, in dentition, odontalgia, 

 and painful nervous affections from organic and inorganic 

 lesions generally. 



" The phenomena which we have now described, first from 

 our own observations and then from those of Dr. Marshall 

 Hall, have all this in common with one another, that the spinal 



* These and other acts of the excito-motory system are attended by sen- 

 sation, but are not the less independent of it ; some are entirely without it. 

 — M. H. 



