510 THE BRAIN. 



facial nerves which animate the muscles of the tongue and lips, as well 

 as the motor fibres which regulate the condition of the rima glottidis. 

 Disease or injury in this situation, sufficient to impair the action of these 

 nerves, consequently makes articulation difficult or impossible, by para- 

 lyzing the muscles upon which it is dependent. This affection is quite 

 distinct from " aphasia," which is of cerebral origin and consists in a 

 loss or deterioration of mental faculties alone, the external mechanism 

 of speech being unaffected and the muscles of the tongue and lips re- 

 taining their power of movement in any direction. When the difficulty 

 is seated in the medulla, on the other hand, the muscular paralysis is 

 very evident, and is distinguished by being more or less confined to 

 those groups of muscles which are concerned in articulation and phona- 

 tion. 



Such an affection is that first described by Duchenne and now gene- 

 rally recognized under the name of glosso-labio-laryngeal paralysis. 1 It 

 is a paralysis due to chronic degeneration of gray nervous tissue in the 

 medulla oblongata, which affects the motor nerves of the tongue, the 

 face, the hanging palate, and the larynx. The first difficulty is generally 

 noticeable in the movements of the tongue, which cannot be applied 

 accurately to the upper teeth or to the roof of the mouth ; and the 

 lingual and dental consonants are therefore pronounced imperfectly or 

 not at all. The lips are next affected, so that they cannot be brought 

 in contact with each other, and B and P are pronounced like Y or F. 

 As the debility of the orbicularis oris increases, the lips cannot even be 

 partially approximated and the vowels and U are no longer sounded ; 

 and by the continued exaggeration of these difficulties the patient's 

 speech becomes at last unintelligible. Deglutition is also affected, and 

 attempts at swallowing are liable to cause choking, from the imperfect 

 protection of the rima glottidis. Phonation becomes impaired from 

 debility of the laryngeal muscles, and in advanced cases no vocal sound 

 can be produced. The disease is uniformly progressive, and terminates 

 life usually by affecting the movements of respiration. 



The medulla oblongata is accordingly the seat of reflex actions which 

 are directly or indirectly connected with the immediate preservation of 

 life, since it maintains the movements by which air and food are intro- 

 duced into the interior of the body. It also presides over the immediate 

 muscular combinations concerned in the production of the voice and 

 articulation, and by this means establishes an intelligible communica- 

 tion with the external world. 



1 Hammond, Diseases of the Nervous System. New York, 1871, p. 676. 



