THE BRAIN. 445 



speech is unaffected, the muscles of the tongue and lips retaining their 

 normal power of movement. In disease of the medulla, on the other 

 hand, the muscular paralysis is very evident, and is mainly confined 

 to the muscles of articulation and phonation. 



Such a disease is that known as glosso-labio-laryngeal paralysis. 

 It is a paralysis due to chronic degeneration of the gray substance in 

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

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

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

 applied accurately to the teeth or the roof of the mouth ; the lingual 

 and dental consonants being 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, entirely preventing 

 approximation of the lips, 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 

 the attempt to swallow is liable to cause choking from imperfect pro- 

 tection 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 usually termi- 

 nates by affecting the movements of respiration. 



The medulla oblongata is, accordingly, the seat of reflex actions con- 

 nected with the immediate preservation of life, since it maintains the 

 movements by which air and food are introduced into the body. It 

 also presides over the muscular combinations concerned in the voice 

 and articulation, and by this means establishes an intelligible commu- 

 nication with the external world. 



