604 THE POSTERIOR PITUITARY AND THE NERVOUS SYSTEM. 



which must be emphasized: i.e., the identity of the posterior 

 pituitary body as the center upon which all emotions, shock, 

 etc., react, and as the organ which initiates the phenomena 

 that attend the impressions thus produced. 



That this organ is directly or indirectly connected with 

 the cerebrum in all phenomena pertaining to intelligence, 

 reason, and will, precisely as its motor functions other than 

 the purely automatic ones may be dominated by these higher 

 manifestations of nervous activity, need hardly be emphasized. 

 "Sensory" interpreted by us i.e., in its broad sense refers 

 to impressions received by all end-organs endowed with sensa- 

 tion, as previously stated. Whether these first reach the eye, 

 the ear, the cutaneous surface, the gustatory papillae, the olfac- 

 tory area, etc., or be due to traumatism, surgical procedures, 

 an abnormal mental state, such as attends fear, grief, or other 

 emotions, etc., we are always dealing with molecular jarring 

 of the posterior pituitary body: harmless when slight, patho- 

 genic when sufficiently intense, but fatal when a certain limit 

 is reached. Precisely as the current passed through the region 

 by the Weber brothers inhibited the heart, so can fright, in- 

 tense pleasure, or shock prove fatal by inhibiting the heart, 

 but primarily by jarring the posterior pituitary body or, 

 speaking more correctly, by inducing excessive molecular vibra- 

 tion of its elements. 



The maximum effect of shock thus becomes an arrest of 

 nervous impulses through which function is sustained via the 

 cerebro-spinal axis. This may well be illustrated by the de- 

 scription given by Professor Stewart of the "various phenomena 

 which are grouped together under the name of shock" as ex- 

 emplified by section of the cord. "When the spinal cord of a 

 dog is divided, e.g., in the dorsal region, all power all 

 vitality, one might almost say seems to be forever gone from 

 the portion of the body below the level of the section. The 

 legs hang limp and useless. Pinching or tickling them calls 

 forth no reflex movements. The vasomotor tone is destroyed, 

 and the vessels gorged with blood. The urine accumulates, 

 overfills the paralyzed bladder, and continually dribbles away 

 from it. The sphincter of the anus has lost its tone, and the 

 faaces escape involuntarily." We hardly need to emphasize the 



