486 THE POSTERIOR PITUITARY AND THE NERVOUS SYSTEM. 



frog) the first structure reached by the current after the nasal 

 structures would be the infundibular portion of the third ven- 

 tricle: i.e., that connected with the posterior pituitary lobe. 

 Again, and very suggestive, is the fact that these structures and 

 all those falling in the line of the current form part of what 

 Professor Foster terms "in point of origin the oldest part of 

 the brain" and "the central gray matter" which "seems to 

 serve chiefly as a bed for the development of the nuclei of 

 the cranial nerves." Indeed, we might add that, according 

 to Eeichert, 2 "one center has been located in the rabbit in the 

 tuber cinereum, which has been named a polypnceic center 

 because, when excited, the respirations are rendered extremely 

 frequent." . . . "Another area has been located in the 

 optic thalamus, in the floor of the third ventricle; this center," 

 says the author, "is believed to be excited by impulses carried 

 by the nerves of sight and hearing, and when irritated causes 

 an acceleration of the respiratory rate." 



The more dorsal portion of the current would strike a 

 no less important physiological region. "Next to the central 

 gray matter," says Professor Foster, "and more or less asso- 

 ciated with it, comes what is called the tegmental region, of 

 which the reticular formation coming into prominence in the 

 bulb and continued on to the subthalamic region, forms, as it 

 were, the core. Belonging to the tegmental system are nu- 

 merous masses of gray matter from the conspicuous optic 

 thalamus and the red nucleus in front to the several nuclei of 

 the bulb behind. This complex tegmental system, which may, 

 perhaps, be regarded as a more or less continuous column of 

 .gray matter, comparable to the gray matter of the spinal cord, 

 serves as a sort of 'backbone to the rest of the central nervous 

 system" 



The morbid effects of the current become normal conse- 

 quences when we consider that the structures traversed by it 

 include those that even emotions will disturb. Referring to 

 the posterior portion of the pons, that adjoining the tissues 

 that form the fourth ventricle and which represents the down- 

 ward continuation of the tegmentum, Professor Duval says: 

 "It is, indeed, to the pons that we seem to be authorized to 



3 Reichert: Loc. cit., p. 457. 



