442 THE BRAIN. 



and third cervical nerves, both the phrenic and intercostal nerves 

 are at once paralyzed, and death necessarily takes place from suf- 

 focation. The attempt at respiration, however, still continues in 

 these cases, showing itself by ineffectual inspiratory movements of 

 the mouth and nostrils. Finally, if the medulla itself be broken up 

 by a steel instrument introduced through the foramen magnum, so 

 as to destroy the nervous centre in which the above reflex action 

 takes place, both the power and the desire to breathe are at once 

 taken away. No attempt is made at inspiration, there is no strug- 

 gle, and no appearance of suffering. The animal dies simply by 

 a want of aeration of the blood, which leads in a few moments to 

 an arrest of the circulation. 



It is owing to the above action of the medulla oblongata that in- 

 juries of this part are so promptly and constantly fatal. When the 

 " neck is broken," as in hanging or by sudden falls upon the head, 

 a rupture takes place of the transverse ligament of the atlas ; the 

 head, together with the first cervical vertebra, is allowed to slide 

 forward, and the medulla is compressed between the odontoid pro- 

 cess of the axis in front and the posterior part of the arch of the 

 atlas behind. In cases of apoplexy, where any part of the hemi- 

 spheres, corpora striata, or optic thalarni, is the seat of the hemor- 

 rhage, the patient generally lives at least twelve hours ; but if the 

 hemorrhage takes place into the medulla itself, or at the base of the 

 brain in its immediate neighborhood, so as to compress its sub- 

 stance, death follows instantaneously, and by the same mechanism 

 as where the medulla is intentionally destroyed. 



An irregularity or want of correspondence in the movements of 

 respiration is accordingly found to be one of the most threatening 

 of all symptoms in affections of the brain. A disturbance or sus- 

 pension of the intellectual powers does not indicate necessarily any 

 immediate danger to life. Even sensation and volition may be im- 

 paired without serious and direct injury to the organic functions. 

 These symptoms only indicate the threatening progress of the dis- 

 ease, and show that it is gradually approaching the vital centre. It 

 is common to see, however, as the medulla itself begins to be impli- 

 cated, a paralysis first showing itself in the respiratory movements 

 of the nostrils and lips, while those of the chest and abdomen still 

 go on as usual. The cheeks are then drawn in with every inspira- 

 tion and puffed out sluggishly with every expiration, the nostrils 

 themselves sometimes participating in these unnatural movements. 

 A still more threatening symptom, and one which frequently pre- 



