Dynamic Theory. 

 across the optic chiasm into the optic " tract " (e). But there are cases 

 in which the injury is communicated to the optic tract on the same side 

 as the atrophied nerve ( See fig. 369 ). The right side of each eve is 

 connected with the right side of the brain, and the left of each eye 

 with the left side of the brain. 



Hysteria appears to be due to a letting down of some of the nervous 

 elements, probably from prolonged or undue erethism or excitement, so 

 that they no longer enter their influence in the formation of the will. 



FIG. 377. Diagram of Optic Nerves, show- 

 ing' atrophy following the destruction of an 

 eye. (Owen.) 



a. Atrophied nerve, leading to lost eye. 



6. Nerve leading to the sound eye. 



c. Optic Chiasm. 



d. Optic Tract, more of which is connected 

 with b than with a. 



e. Optic Tract partly atrophied in connec- 

 tion with a. ( See tig. 369.) 



The elements thus affected to produce 

 hysteria are either some of those 

 which are concerned in the social func- 

 tions and relations, or are nearly con- 

 nected with them. The morbid ac- 

 tion requires for its stimulus the 

 FIG. 377. presence of an audience. To this 



audience the patient morbidly appeals for sympathy, admiration, &c. 

 To work upon her audience effectually, she will often resort to decep- 

 tion, first perhaps becoming deceived herself. Such patients will feign a 

 great variety of diseases, and pretend to various disabilities which exist 

 only in the imagination. The disease is, or includes, a letting down of 

 the machinery of the moral sensibilities, and is a process of the undo- 

 ing of some, of the results of social evolution. When paralysis, or 

 blindness, or speechlessness is feigned, as is often the case, while there 

 is nothing at all the matter with the nerves of motion, the organs of 

 speech or of sight, the disease and the disability are still as real as if 

 these organs were visibly injured. The seat of the trouble is in those 

 cerebral ganglia which lie between the memory cells of sensation and 

 the nerves of motion ; those ganglia which are differentiated after birth 

 and during the educational period of life, and which register those rela- 

 tionships in the environment that are ascertained by those cerebral inter- 

 actions which make up what is commonly called reflection. They be- 

 long to the class of ganglia which are described as being the seat of the 

 internal senses. The healthy action of the internal senses is essential 

 to the formation of a properly balanced purposive will. When any of 

 these centers fail, therefore, from inadequate nourishment, it is the will 

 itself which becomes distorted, eccentric, and only half made up. The 

 want of a will is just as effectual a bar to the movement of a muscle as 



